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jerry davis · 09-26-2019, 10:20 AM

Hoping someone has had this same issue:

No hot water present. Turn on bypass switch and hot water is present. Turn off bypass switch and hot water is present for several days and system performs normally. This scenario has repeated itself three times now. I called ITR and they really weren’t much help. They said maybe a loose connection or bad summer loop pump.
Any suggestions?

Webz · 09-26-2019, 10:39 AM

You may want to check the 110 volt wires going to the burner box. They are connected with wire nuts. (Not the best for something that moves) ITR has always been very helpful to me. An intermittent pump could be the problem but in my experience either they work or they don't. I would lean towards a loose wire. The wires going to the pumps are a regular spade connection. Getting to them is the fun part. Are you familiar with the pumps location? I would definitely check the 110 volt wires to rule them out from a safety point of view. I'm sure others will have some ideas also.

ptw · 09-26-2019, 12:32 PM

The summer loop pump will not initially turn on until the fluid reaches a set temperature. Do you have the oil burner on when you are doing this? If you are using electric, is it possible the fluid hasn't reached the correct temperature? When you turn on the bypass switch you turn on the heat loop pumps to get hot water.

My guess is you have a sticking summer loop pump or a bad temperature sensor (lose wire?). Also, the previous poster mentioned the 110 V power lines. It always good to check your coach ammeter when you turn on AC1 and AC2. By running hot water faucets you should see the electric elements turn on. Verify that by turning AC1/AC2 off and on you should pick up about 12 amps on each side of your incoming line for a total of about 24 amps.

Here is the service manual if you want to continue to resolve this problem on you own.

RetireeKeith · 09-27-2019, 05:05 PM

It could be an aquastat mechanism that is sticking. There is an aquastat (water temperature switch) that senses when cold water is coming (when you turn on a hot water faucet) into the tiny potable water plate heat exchnager that is inside your distribution module cabinet at the top. The heat exchanger is what heats up ypur potable water. If your space heating loop pumps are not operating (space heating is not called for), the switch turns on the summer loop pump to circulate hot glycol through the warm side of the plate heat exchanger to heat the cold water on the other side of the plates. The aquastat is located at the top of the cabinet where the cold water pipe comes in. The aquastat is clamped onto the oputside of the cold water line in a flimsy way and could also become lose so it does not contact the pipe well. When I replaced my aquastat, I wrapped aluminum foil tape around the switch to reinforce the connection to the pipe.

I am surprised the guys at the manufacturer, Iternational Thermal Research, were not much help. They are usually excellent.

Keith

jerry davis · 10-03-2019, 03:37 PM

To finish up this post;
I went ahead and changed out the summer pump. It’s been a week now with no problems. Apparently the old pump worked intermittently. Glad I carry a spare pump.

ptw · 10-03-2019, 05:16 PM

Glad you got it fixed. My first summer loop pump lasted around 6 months. I have around 2 1/2 years on the second one now. We also keep a spare.

Stealth01 · 10-04-2019, 09:50 AM

ptw,
IF the issue recurs, look at the aquastats!! Having said that and just for your edification, the pumps are magnetically coupled! In the photo of one of my failed pumps you can see where the magnetic shaft has split. As the centrifugal force of the shaft spinning causes the crack to grow and expand the shaft begins to drag on the housing. This failure tends to occur over time and thus the failure can be intermittent! I had a pump I nursed for a year before it hard failed!