Heater Re-plumb

I have a 45,000 btu Hurricane heater with 4 bus-type heaters, 3 with seperate thermostats. I am planning to replace the elderly hoses and remove the engine-mounted heat exchanger that heats the water heater and uses engine coolant to heat the boat while running, as well as add a closed water tank instead of the reservoir that is mounted high but open to the atmosphere.

Right now, the radiators are daisy-chained and I have been contemplating a manifold system with each rad. on its own loop with an individual valve to control the flow to each area as the longer loops will require more flow than those closest to the heater. House water system and in-floor heating systems use manifolds so I can use a household part.

I am also planning to use Pex.

Comments? Can anyone recount their heater experiences and add anything to this plan?

just curious about getting rid of the heat exchange....reason?

pex seems fine, what kind of fittings and are you planning to use the special pex for hydronic?

I thought when I was investigating my heater they discussed pex better suited for recirc versus straight plumbing.

Also switching to closed I guess you'll need a safety pressure relief...although if using the engine coolant the radiator cap really is it.

I would go with separate loops...maybe not all 4 on a manifold...but not all daisy chained either.

good pricing and great service
https://www.supplyhouse.com/pex/control/myAccount

inexpensive booster pump
https://www.supplyhouse.com/pex/control/myAccount

seemed like a good exchanger if you want to keep that sstem
https://www.brazetek.com/products

Pex is for dirt houses where its sealed in the walls or under the floor.

Every engine space has work happening , oil change , R&R something .

Std rubber hose and fittings can be pushed on stomped on and still work with no leaking.

The funds saved with house plastic tubing will never allow a good nights sleep , even a month after some engine room fun.

I am removing the heat exchanger for simplicity. I am still using a loop of coolant for my Torrid heater so the engine will heat the water but having my boiler heat the engine block seems a waste of time. For the small amount of fuel it burns, I can just run the heater when it gets chilly.

I planned the radiant Pex pipe. I have no cast iron in my heat system(!) so I don't need oxygen block. I plan a stainless manifold and will secure all the pipe so I don't have to worry like FF seems to. All the pipe will be under the floorboards. Another reason to remove the heater hose is to get rid of all the damn hose clamps that rust and leak and damage the hose.

Daisy chaining is a stupid system as the radiators farthest from the boiler are already being run through a couple of other radiators so they are pre-cooled. The down side is all the additional piping which adds complexity but also simplifies installation and troubleshooting.

Xsbank said:

I have a 45,000 btu Hurricane heater with 4 bus-type heaters, 3 with seperate thermostats. I am planning to replace the elderly hoses and remove the engine-mounted heat exchanger that heats the water heater and uses engine coolant to heat the boat while running, as well as add a closed water tank instead of the reservoir that is mounted high but open to the atmosphere.

Right now, the radiators are daisy-chained and I have been contemplating a manifold system with each rad. on its own loop with an individual valve to control the flow to each area as the longer loops will require more flow than those closest to the heater. House water system and in-floor heating systems use manifolds so I can use a household part.

I am also planning to use Pex.

Comments? Can anyone recount their heater experiences and add anything to this plan?

Click to expand...

That sounds like it describes our system. I used 120 vac electric valves that open on a call for heat from a zone and positively close when set point is reached. These are nice because other types of hydronic valves tend to allow hot water to continue to circulate, even if minimally, in these low pressure systems. I circulate boiler coolant which lasts around 4 to 5 years.

A drawing I did for our system is below.