Tecma Head Solenoid

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Datenight

Guru
Joined
Jan 9, 2008
Messages
1,132
Location
USA
Vessel Name
Datenight
Vessel Make
North Pacific 45
As is so often the case our Tecma head which has been flawless for the past four seasons is acting up on our first cruise of 2024. It tested fine at the dock. It will flush but not let water into the bowl before or during the flush. Our temporary solution is a bucket of water before and after use. Seems to work.

I get a click at the control panel but nothing at the water inlet solenoid. I suspect the solenoid is bad. Any thought as to whether this is a proprietary valve or an off the shelf product?
Thanks,
Rob
 

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It looks somewhat generic. I believe any 12 volt solenoid rated for water with the correct inlet/outlet threads will work.
When i converted my Jabsco to tank water flush i bought a solenoid via the nternet that fit my plumbing.
I worked for a company that manufactured solenoid valves and they are pretty basic. IF you can take this one apart you might find that its corroded internally and you might be able to free it up.
 
The problem could also be the wiring or a fuse. You can test the solenoid by applying 12 volts to it and see if it works or not.

If it still does not, as mentioned above, it could be stuck from sediments or corrosion. You can try to take it apart or tap it to see if it loosens up.

Good luck!
 
It is a generic RobertShaw valve. However, trying to cross reference it based on the part numbers printed on the valve label in your photo is not giving me a suitable answer. RobertShaw makes a lot of valves!
Seems like the best way to go is to buy a Thetford part. Parts are available from Defender, Fisheries and a number of RV dealers online. Versions of the Tecma Silence are 1G and 2G and 2Gplus. They apparently have different valves. The one shown in my screen capture below looks like the valve in your photo. Which model Tecma is on your 45?

We have the Tecma Silence head on our NP 45. When I asked a dealer at the Seattle Boat Show what spares I should carry, they said "none". Nothing breaks on the Tecma. A couple of years later, they said "maybe the solenoid valve". I believe they said it was about $120. Your experience has now put that spare on my list!
 

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I just did a very quick video nternet search for “ 12 volt water solenoid valve” and got several hits. Less than $50 on Amazon. You should be able to match up something that will work fine.
 
Hi Datenight! Curious to hear how you solved the water flow problem in your Tecma head. Was it the solenoid valve? If so, what did you use for a replacement. If not the valve, then what was the issue? Thanks!
 
Did you check voltage at the solenoid when you pressed the controller. You should rule out the controller
 
Thanks for all the replies and sorry for the delay in getting back to you all. I just got back from Annapolis where I installed a new coolant circulating pump in my brother-in-laws Yanmar 3GM30F.
Defender does carry the valve but I ordered a 2 pack from Amazon for $10.00. Had to make a trip to the hardware store for two plumbing adaptors which added another $6.00ish.

When I took the old valve I saw what seems to be the problem. The intake screen on the valve is at least (see photo) 95% blocked. I will reinstall it tomorrow after cleaning. Seems like I need a filter before the waterpump. Thanks for all the replies.

Rob
 

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Good find! I'll have to check that out on ours. We installed a water heater this spring and I found bits of blue Pex when I cleaned out the screens in the faucets. Didn't think about looking at the head.
 
Hi Datenight! Curious to hear how you solved the water flow problem in your Tecma head. Was it the solenoid valve? If so, what did you use for a replacement. If not the valve, then what was the issue? Thanks!
I was having occasional/random issues with my 21 year old, never serviced, fresh water only flush Tecma. After long periods, overnight for example, push the button and no water ran into the bowl.
Assumed it was a solenoid failure, although local agent suggested a blocked vent valve, turned out to be a slow water pressure leak in the supply line to the heads Vanity (as the toilet solenoid and water supply pipe is right next to the vanity mixer tap).
Until I find the leak, a quick blast of water at the tap brings the supply to the solenoid, then push the toilet flush, and away it goes.
I was definitely over-thinking the problem in the first place, these toilets are incredible at long lasting.
 
Don't know why the photo is so dark. Very clear on my phone.
 
Glad you got it solved so easily!

Jay Leonard

Not so fast Jay! Did not get to the boat until today. I put the cleaned solenoid in and no joy. Installed the new one and could feel it clicking but no water. Traced the water lines and found a valve I had turned off. Turned it on and what do you know, water at the head! Oh well, the old valve needed cleaning any way. I put the old one back in and now I have two replacements and the needed plumbing parts ready to go.

The simplest things...

Rob
 
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