Problem with the boiler..... Losing pressure?

[Lisa_Louise]

Hi

We are renting a house and since we have moved in a month ago we have had problems with the combi boiler. Basically what is happening is when someone goes to use the hot tap the boiler will try and fire up but the pilot light goes out and the pressure goes down to lower than 1. What we have been shown by the landlords maintenance guy is to turn the boiler tap (top the boiler up) back to number 2..... at first this was happening about once every 2 or 3 days, Now it's happening at least once a day.

It is not limited to when the heating is off, it has done it once with the heating on. It is at the point now where it is inconvenient especially when you are about to jump in the shower or have a bath!

Another problem is when the heating is on the hot water is scolding hot, even with the water temp turned right down. We've had the landlord's maintenance guy in, taking up the carpet and looking at the pipes by the rad in the hallway, no leaks at all, bone dry... he's checked the outlet for the boiler in the garden, nothing wrong there, not leaking.... He has called in someone who deals with boilers and he is stumped too!!

Anyone have any ideas what this could be.... my husband struggled to get the pilot to light again this morning when I went to wash my hair, so it's getting worse. I've been asked by the boiler guy to check the outside pipe in the morning and phone him back.........

[fraserstuart]

sounds like a leak check all radiator valves when system is cold a small leak is enough to cause this

[The Builder]

With loss of pressure in a combi, the first thing is to re-charge the pressure vessel. When water heats, it expands. An air charge in the vessel acts as a cushion and "soaks up" the excess pressure. If it can't do this, water is blown out of a safety valve. That's why the pressure drops.
Usually, vessels are charged with a bicycle pump or a foot pump.

If not that, then maybe faulty pressure valve, blowing off too soon.

With the hot water. First thing to check is a simple (cheap) thermistor that controls the water temperature (like a thermostat.)

[Lisa_Louise]

Fraserstuart, thanks, will try that :)

[Lisa_Louise]

Thanks, thebuilder, that's quite complex lol!!! I will show this to my H :)

[Lisa_Louise]

Quick update..... I checked the outlet pipe this morning, I was asked to my my finger in the pipe to see if it was wet, it was...... he says that is a problem and has ordered a part to seeif this is a remedy....... so, is a wet outlet pipe from the boiler a bad sign?

[The Builder]

Lol Lisa .......... only to us ;o)
A decent boiler guy would understand ;o)

He's asked you to look at the outside pipe. That's where the water will show after it's been blown out (as in my explanation above.)

[ChuckFickens]

must. resist. temptation.

[The Builder]

............. just count to a hundred in hexadecimal Chuck ;o)