Low pressure in shower after new thermostat fitted

[Richard B]

Hello. This is my first post on here, so please be gentle with me...

We have a house with electric only heating, and all the hot water comes from a dual element immersion tank. Recently the main thermostat failed, causing the hot water tank to boil, and blow back into the cold water header. I changed the thermostat and was limited to what I could use by the size of the head unit - a Heatrae one (7 inch, horizontal) fitted but most others did not. The Heatrae only goes up to 60 C maximum setting, the previous one was set (not by me) to about 70 C.

The problem now is that the hot water flow from our downstairs shower is much lower than before. I can think of two possible reasons:
1) The temperature is too low, so the mixer tap can't get enough hot water to work correctly.
2) There is a blockage caused by something coming lose when the tank boiled.

I think it is probably the first one, but I'm not sure. It might be something else I haven't thought of at all. Is there any way I can tell what is going on, without buying yet another new thermostat?

Thanks in advance for any help.

 

[Chuck]

The problem now is that the hot water flow from our downstairs shower is much lower than before. I can think of two possible reasons:
1) The temperature is too low, so the mixer tap can't get enough hot water to work correctly.
2) There is a blockage caused by something coming lose when the tank boiled.

I think it is probably the first one, but I'm not sure.

If it were the first one, I'd expect the shower to achieve the same flow as before the incident but the temperature of the water being delivered would be too low.

A simple thermostat fault should not have caused a tank to boil. There should also be a safety cut-out to prevent this happening. A boiling tank is very dangerous. I'd recommend you get a qualified plumber to check your system's safety and performance.

 

[Richard B]

Sorry, Chuck, for my lateness in replying. I have fitted a different thermostat (Sunvic 3000), which has partially solved the problem. The temperature is now much better, although not as good as before.

I think that the previous owners of the house has fitted a thermostat without a cutout (or with a faulty cutout) to achieve higher temperatures. It was branded Pullin, and I think that name is now defunct.