Velair A/C Anyone?

[angus99]

I’ve been looking at this line of Italian-made, self-contained, variable-speed compressor units to replace three split systems. (Note that the 7K btu model shown is not variable speed.)

https://www.uflexusa.com/wp-content/uploads/2021/08/Brochure-pages.pdf

These seem to have a lot going for them. I spoke to an engineer at Uflex Marine, an independent installer and a couple of owners and the feedback has been consistent:

—low amp draws and inverter-friendly—able to run on a suitably sized house bank
—no start-up surges; compressors and fans ramp up and down with demand, similar to household variable-speed units
—extremely quiet operation
—WiFi-controllable

The Velair line is reportedly manufactured at the same facility that builds the crazy expensive Frigomar line using many of the same design features and parts. Uflex, an 80+ year-old company, is planning to unveil a new line this fall that they claim will be 20% more efficient and priced lower. They are also standing up a more robust North American dealer and support network.

Potential downsides include their somewhat larger size, questionable parts availability and limited feedback from actual users.

So, I’m looking for folks with direct or indirect experience with Velair. Based on the two mentions of Velair in the archives, I’m not terribly optimistic.

 

[O C Diver]

Ramp up starts would certainly be an advantage for both inverters and generators, but their power consumption is only ok, not revolutionary. I like how they talk about the much more efficient blower power consumption. Blowers are insignificant compared to compressors relative to power consumption. Btw, the last thing you want on a boat AC system is poor air flow (a number of threads on the forum about evaporators freezing up, almost always from insufficient air flow).

My concern would be service. My Webasto units are throw aways just like a home window air conditioner. For the price (<$900 each), I was fine with that. If you're buying a feature rich unit with a significant price tag, are they serviceable, and locally?

Ted

 

[angus99]

Ramp up starts would certainly be an advantage for both inverters and generators, but their power consumption is only ok, not revolutionary. I like how they talk about the much more efficient blower power consumption. Blowers are insignificant compared to compressors relative to power consumption. Btw, the last thing you want on a boat AC system is poor air flow (a number of threads on the forum about evaporators freezing up, almost always from insufficient air flow).

My concern would be service. My Webasto units are throw aways just like a home window air conditioner. For the price (<$900 each), I was fine with that. If you're buying a feature rich unit with a significant price tag, are they serviceable, and locally?

Ted

All good points, Ted; thanks. I do need to inquire about those CFMs. I’m planning to add an additional supply duct and register on the opposite side of our master berth to help air flow.

Which model Webastos do you have and how quiet are they?

I’ve also been checking out Mabru units. They look like an “optimized conventional” design; pricey, but supposedly with 45 decibels at the grates.

 

[O C Diver]

All good points, Ted; thanks. I do need to inquire about those CFMs. I’m planning to add an additional supply duct and register on the opposite side of our master berth to help air flow.

Which model Webastos do you have and how quiet are they?

I’ve also been checking out Mabru units. They look like an “optimized conventional” design; pricey, but supposedly with 45 decibels at the grates.

These are the units I purchased in 2015, they've about doubled in price. Bought during the October boat show sale season, $2,700 for 3 including shipping.

https://www.defender.com/product.js...tu&path=-1|2061076|2061077|2061083&id=1833549

They weren't quiet when I first used them. Electric motors and compressors have a wear in period. Probably especially true of blower motors with sleeve bearings. I would say they're reasonable but not super quiet. The caveat is that the saloon and pilothouse units each have one 24" long supply duct. This makes them super efficient (maximizing cold extraction from the evaporator), but a longer supply would greatly reduce the noise.

45 decibels at the grates is absolutely meaningless. That speaks largely to the length and design of the ductwork. It wouldn't be 45 decibels installed in my saloon with the single 24" supply duct!

Ted

 

[angus99]

45 decibels at the grates is absolutely meaningless. That speaks largely to the length and design of the ductwork. It wouldn't be 45 decibels installed in my saloon with the single 24" supply duct!

Ted

Also speaks to fan speed and cfm being moved, I would think. They actually gave a range of 38-45 db in what they claim was a head-to-head with others, but I haven’t found it on line. It’s all marketing, no?

 

[wfleenor]

I installed 4 Velair units last summer - (3) 16BTU and (1) 21BTU. They function as operated and the Florida person I worked through was very helpful. Two units had funky thermostats and they replaced them imediately.

 

[O C Diver]

Also speaks to fan speed and cfm being moved, I would think. They actually gave a range of 38-45 db in what they claim was a head-to-head with others, but I haven’t found it on line. It’s all marketing, no?

In a perfect world, you want to run the fan speed on auto. The speed is determined by the differential spread between the set point and room temperature. Simply, if the boat is hot when you turn on the AC, you want the fan on high to cool the boat down as quickly as possible. This is fastest and most efficient. As you near the set point, reducing fan speed to medium reduces noise with some loss of BTU capacity. When you're within a degree or so of set point, the fan goes to low for quietest operation but lowest BTU output. To beat this point thoroughly to death, there will be times when the compressor is running where the fan will cycle from low to medium. Most compressors have only one output level when running. When the fan goes to medium, the AC is able to harvest more cold from the evaporator because of increased air flow. So occasionally you will experience the compressor running continuously and the fan speed cycling up and down.

One side note that is annoying about Webasto and some other AC units is the location of the air temperature sensor. The Webastos and some others measure air temperature in front of the evaporator. While it generally works reasonably well, the actual thermostat is part of the electronic control board. What you think is the thermostat is really a remote control panel. Dealing with a bad thermostat involves replacing the control board. Every so often, my pilothouse unit will take the temperature down to the low 60s before the compressor cycles off. It's annoying, but not worth replacing the board over.

Ted

 

[rslifkin]

In a perfect world, you want to run the fan speed on auto. The speed is determined by the differential spread between the set point and room temperature. Simply, if the boat is hot when you turn on the AC, you want the fan on high to cool the boat down as quickly as possible. This is fastest and most efficient. As you near the set point, reducing fan speed to medium reduces noise with some loss of BTU capacity. When you're within a degree or so of set point, the fan goes to low for quietest operation but lowest BTU output. To beat this point thoroughly to death, there will be times when the compressor is running where the fan will cycle from low to medium. Most compressors have only one output level when running. When the fan goes to medium, the AC is able to harvest more cold from the evaporator because of increased air flow. So occasionally you will experience the compressor running continuously and the fan speed cycling up and down.

One side note that is annoying about Webasto and some other AC units is the location of the air temperature sensor. The Webastos and some others measure air temperature in front of the evaporator. While it generally works reasonably well, the actual thermostat is part of the electronic control board. What you think is the thermostat is really a remote control panel. Dealing with a bad thermostat involves replacing the control board. Every so often, my pilothouse unit will take the temperature down to the low 60s before the compressor cycles off. It's annoying, but not worth replacing the board over.

Ted

With the Webasto in my salon, it seems like there's a minimum cycle length that sometimes leads to temperature overshoot. I've also seen issues with using auto fan speed leading to freeze ups. Low speed is just too low, so if it's humid, the evaporator sometimes ices up before it cycles off. Forcing it to high fan in AC mode avoids the issue.

 

[angus99]

In a perfect world, you want to run the fan speed on auto. The speed is determined by the differential spread between the set point and room temperature. Simply, if the boat is hot when you turn on the AC, you want the fan on high to cool the boat down as quickly as possible. This is fastest and most efficient. As you near the set point, reducing fan speed to medium reduces noise with some loss of BTU capacity. When you're within a degree or so of set point, the fan goes to low for quietest operation but lowest BTU output. To beat this point thoroughly to death, there will be times when the compressor is running where the fan will cycle from low to medium. Most compressors have only one output level when running. When the fan goes to medium, the AC is able to harvest more cold from the evaporator because of increased air flow. So occasionally you will experience the compressor running continuously and the fan speed cycling up and down.

Ted

Ted, isn’t the cycle you’re describing the basic way a variable speed compressor/fan is supposed to work automatically? My limited understanding is that these units’ compressors never shut off, but throttle down to very low levels as temps approach the set point. Hence no startup surge when the compressor kicks on.

 

[O C Diver]

Ted, isn’t the cycle you’re describing the basic way a variable speed compressor/fan is supposed to work automatically? My limited understanding is that these units’ compressors never shut off, but throttle down to very low levels as temps approach the set point. Hence no startup surge when the compressor kicks on.

What you are describing may be true in a home system. Not sure the boat system you are considering does that. Frankly I would never buy a system like that where the compressor never shuts off. A ramp up soft start is by definition very different from a variable speed compressor.

Ted

 

[O C Diver]

With the Webasto in my salon, it seems like there's a minimum cycle length that sometimes leads to temperature overshoot. I've also seen issues with using auto fan speed leading to freeze ups. Low speed is just too low, so if it's humid, the evaporator sometimes ices up before it cycles off. Forcing it to high fan in AC mode avoids the issue.

What you are describing is flow restriction in your ductwork design. If you disconnected the ductwork and ran the unit on low fan it would work fine. So the ductwork (either supply, return, or both) reduces the flow through frictional line loss or back pressure. If running the fan on high solves the problem, that's the simplest solution. But the problem isn't the air conditioner, it's the ductwork.

Ted

 

[rslifkin]

What you are describing is flow restriction in your ductwork design. If you disconnected the ductwork and ran the unit on low fan it would work fine. So the ductwork (either supply, return, or both) reduces the flow through frictional line loss or back pressure. If running the fan on high solves the problem, that's the simplest solution. But the problem isn't the air conditioner, it's the ductwork.

Ted

Absolutely correct. On the unit in question, it's about 6 feet of 6" duct with a single sweeping 90 bend in it. Problem is, a good 4.5 feet of that run is a straight vertical rise. So I figure the low speed is just set a bit too low to account for anything other than a very short, straight outlet duct. The old Marine Air Turbo units I had previously had fancier controllers with the ability to adjust the minimum fan speed to account for that, but unfortunately the units were unreliable pieces of junk.

 

[angus99]

What you are describing may be true in a home system. Not sure the boat system you are considering does that. Frankly I would never buy a system like that where the compressor never shuts off. A ramp up soft start is by definition very different from a variable speed compressor.

Ted

Yes, I misstated the soft start part, but these are not our grandfathers’ A/C systems anymore. They’re are designed from the ground up to run continuously, ramp up with no inrush of current and vary compressor/fan speed to match cooling/heating demands.

This isn’t Velair’s literature, but their engineer and leading installer both described the Velair units in very similar terms to me.

https://www.danfoss.com/en-us/marke...conditioning/dcs/variable-speed/#tab-overview

 

[O C Diver]

Yes, I misstated the soft start part, but these are not our grandfathers’ A/C systems anymore. They’re are designed from the ground up to run continuously, ramp up with no inrush of current and vary compressor/fan speed to match cooling/heating demands.

This isn’t Velair’s literature, but their engineer and leading installer both described the Velair units in very similar terms to me.

https://www.danfoss.com/en-us/marke...conditioning/dcs/variable-speed/#tab-overview

I would expect in an application where a routine number of cycles per hour are expected such as home or commercial refrigerators or freezers, that there may be a case for continuous variable speed compressors. In a building where the outside air temperature is always above the desired inside air temperature, I would keep an open mind. But that's about where it ends.

Currently in Fort Myers FL, my pilothouse AC would start cycling around noon and stop by 6 PM. Sorry, I'm not buying the logic for running the compressor for 18 hours without the need to generate cooling during that time. If the weather turns cold for 5 days, does it make sense to run the compressor for 100 hours without need? Truth be known, I only run a dehumidifier unless I'm working on the boat this time of year.

3 years ago when I replaced my Florida home heat pump, the salesman was all about continuous variable speed fans and compressors. The advantage is about uniform temperature and humidity control throughout the whole house. It doesn't come with a lower electric bill. My home system does have a soft startup compressor and variable speed ramp up blower. A power surge or nearby lightning strike toasted the variable speed blower motor and its control board. If not covered under warranty, it would have been between $1,000 and $1,300. The old fashion blower motor is <$150.

I find it amusing that new cars turn themselves off waiting at a traffic light to save fuel and the planet, but refrigeration compressors are now supposed to run continuously.

Ted

 

[rslifkin]

I would expect in an application where a routine number of cycles per hour are expected such as home or commercial refrigerators or freezers, that there may be a case for continuous variable speed compressors. In a building where the outside air temperature is always above the desired inside air temperature, I would keep an open mind. But that's about where it ends.

Currently in Fort Myers FL, my pilothouse AC would start cycling around noon and stop by 6 PM. Sorry, I'm not buying the logic for running the compressor for 18 hours without the need to generate cooling during that time. If the weather turns cold for 5 days, does it make sense to run the compressor for 100 hours without need? Truth be known, I only run a dehumidifier unless I'm working on the boat this time of year.

3 years ago when I replaced my Florida home heat pump, the salesman was all about continuous variable speed fans and compressors. The advantage is about uniform temperature and humidity control throughout the whole house. It doesn't come with a lower electric bill. My home system does have a soft startup compressor and variable speed ramp up blower. A power surge or nearby lightning strike toasted the variable speed blower motor and its control board. If not covered under warranty, it would have been between $1,000 and $1,300. The old fashion blower motor is <$150.

I find it amusing that new cars turn themselves off waiting at a traffic light to save fuel and the planet, but refrigeration compressors are now supposed to run continuously.

Ted

Unless the control logic is terrible, the variable speed compressor should shut off if it's down to minimum speed and you dip below the set point, so it should still shut off overnight. It's just during the day where it would run continuously at low power instead of cycling on and off at full blast. The unit running at low speed to maintain temperature and only throttling up when it needs to also should keep the inside temp more constant (more comfortable). Basically, it would run at varying speeds to maintain temp, but once cooling demand is less than the output of the unit throttled down to minimum, it'll still shut off.

 

[O C Diver]

Unless the control logic is terrible, the variable speed compressor should shut off if it's down to minimum speed and you dip below the set point, so it should still shut off overnight. It's just during the day where it would run continuously at low power instead of cycling on and off at full blast. The unit running at low speed to maintain temperature and only throttling up when it needs to also should keep the inside temp more constant (more comfortable). Basically, it would run at varying speeds to maintain temp, but once cooling demand is less than the output of the unit throttled down to minimum, it'll still shut off.

Guess I'm old school. My differential between heating and air conditioning is about 7 degrees. I just don't see your scenario as a money saver. Here in SWFL HVAC units last about 10 years. I just don't see the extra compressor hours extending the life of my HVAC or lowering my electric bill.

Ted

 

[rslifkin]

Guess I'm old school. My differential between heating and air conditioning is about 7 degrees. I just don't see your scenario as a money saver. Here in SWFL HVAC units last about 10 years. I just don't see the extra compressor hours extending the life of my HVAC or lowering my electric bill.

Ted

I don't know about the compressor lifespan concern, but variable speed is not necessarily more efficient. It could be slightly if the compressor efficiency either improves when slowed down or stays the same (less loss to system pump down at startup). The primary benefit is tighter temperature regulation. I wouldn't spend a bunch of extra money on it without enough other benefit though.

 

[angus99]

Frigomar has been marketing variable speed drive units since 2013 (at obscene prices). Velair, which reportedly uses the same factory and components, introduced theirs in 2019 at a lower, but still higher than average, price point. Mabru has just introduced a 17K Btu VSD unit, also high dollar, but they use copper condensers and warrant their (rotary) compressors for life.

Installers I’ve spoken with believe VSD is the coming wave. I don’t know enough HVAC tech to argue with you guys, but the claims these companies make, if true, seem impressive—4.5 to 8 amp draw for a unit that can deliver 4,000 to 17,000 Btu, depending on the demand. That certainly beats my Cruisars—and for my oldest unit, a bucket of marbles would be quieter.

I’m hanging back for now and hoping more real world experience shows up. Here’s an example of one purported Velair customer’s results.

 

[O C Diver]

Frigomar has been marketing variable speed drive units since 2013 (at obscene prices). Velair, which reportedly uses the same factory and components, introduced theirs in 2019 at a lower, but still higher than average, price point. Mabru has just introduced a 17K Btu VSD unit, also high dollar, but they use copper condensers and warrant their (rotary) compressors for life.

Installers I’ve spoken with believe VSD is the coming wave. I don’t know enough HVAC tech to argue with you guys, but the claims these companies make, if true, seem impressive—4.5 to 8 amp draw for a unit that can deliver 4,000 to 17,000 Btu, depending on the demand. That certainly beats my Cruisars—and for my oldest unit, a bucket of marbles would be quieter.

I’m hanging back for now and hoping more real world experience shows up. Here’s an example of one purported Velair customer’s results.

4.5 amps for 4,000 BTUs doesn't impress me. My Webasto 12,000 BTU unit pulls 10 amps for 12,000 BTUs. Now if they truly get 17,000 BTUs from 8 amps, that would impress me!

Ted

 

[LarryM]

Looks like variable speed compressors are the new direction of marine air conditioning systems.

Dometic just introduced their new Voyager Series Variable Capacity air conditioning systems.

From their press release:

"By utilizing a variable speed compressor (instead of a fixed speed one), the Voyager Series TX provides vessel owners with substantial energy cost savings. Extensive Dometic testing has shown that replacing existing systems with Dometic’s Voyager Series TX can net as much as 40% reduction in amperage. (own comparison)"

"Dometic’s Voyager Series TX offers another important advantage for vessel owners. Longer sustained run cycles reduce wear and tear on the unit, when compared to the repeated start/stop operation of traditional units. This can help reduce repair costs and troublesome downtime — something no boater wants during the heat of the boating season."

"The Voyager Series TX well-thought-out design includes a robust titanium condenser, an electronic expansion valve for precise control, a removable electric box that can be remote mounted, and a compact overall size for versatile installation and retrofits aboard a wide variety of vessels. Dometic has also combined the control/inverter into a single, space-efficient design for easier and more versatile installation."

Might be worth a look when their suppliers get them in stock.

 

[angus99]

Looks like variable speed compressors are the new direction of marine air conditioning systems.

Dometic just introduced their new Voyager Series Variable Capacity air conditioning systems.

From their press release:

"By utilizing a variable speed compressor (instead of a fixed speed one), the Voyager Series TX provides vessel owners with substantial energy cost savings. Extensive Dometic testing has shown that replacing existing systems with Dometic’s Voyager Series TX can net as much as 40% reduction in amperage. (own comparison)"

"Dometic’s Voyager Series TX offers another important advantage for vessel owners. Longer sustained run cycles reduce wear and tear on the unit, when compared to the repeated start/stop operation of traditional units. This can help reduce repair costs and troublesome downtime — something no boater wants during the heat of the boating season."

"The Voyager Series TX well-thought-out design includes a robust titanium condenser, an electronic expansion valve for precise control, a removable electric box that can be remote mounted, and a compact overall size for versatile installation and retrofits aboard a wide variety of vessels. Dometic has also combined the control/inverter into a single, space-efficient design for easier and more versatile installation."

Might be worth a look when their suppliers get them in stock.

Thank you! I was actually going to call them today to see if they were planning a line of these. The timing is great!

 

[Hapuna Owner]

Velair ac

I have two 16,000 btu units slightly larger than dometics. each run at about 600 watts. Strong blower I use remote access frequently.
I would definitely buy them again. Support has been great, mainly questions about remote access lmk iu want more info.