BOILER GOING TO TOO HIGH A PRESSURE

[JSM]

Hello Helpers,

When I came in tonight the pressure on the boiler seemed unusually low but still within its allowance. I turned the thermostat in the hall up to 30. Thereafter, I realised that the boiler seemed to have been on for a while and when I looked at the needle it as just into the (high) red. I turned the thermostat in the hall back down and the boiler switched off and the pressure gradually dropped as normal. I put the thermostat back onto to about 27 and again I had to turn it down as I feared the boiler's needle was heading for the high red again. Then I had a couple of shots with the thermostat at about 22 and the boiler switched on and then off again as normal.

I'm guessing that the original low pressure may have been a result of the pressure being too high previously without me knowing and discharging some water outside.

I do have a contract with British Gas but I don't want to dive to contact them without taking good advice from your goodselves. Any observations would be most welcome and particularly as to whether I have a problem with the boiler or with the thermostat in the hall.

Thank you in anticipation of your very kind assistance.

 

[kevplumb]

by the sound of it the expansion vessel needs recharging / replacing

is the prv pipe wet

 

[gassafeman]

Expansion Vessel
PRV

Look up FAQ's

 

[JSM]

Hi Guys,

Thanks very much for that.

If PRV means the pipe outside I think the bottom was a wee bit wet but I don't know whether this would be due to rain or not.

Where can I find FAQ?

Finally, and this is a hard one, my contract with British Gas is for the boiler. Am I likely to be covered for the expansion vessel? Is it a big job to recharge/replace?

Many thanks.

 

[kevplumb]

expansion vessel is part of the boiler

faq is at top of forum

 

[gassafeman]

www.diynot.com/forums/viewtopic.php?t=175736

or here www.diynot.com/forums/viewtopic.php?t=37170

Try here

 

[twgas]

you say pressure went from "unusually low" to "high red", why not give us some actual figures read from the gauge so that we can make a much more informed diagnosis.

 

[JSM]

Hi,

Happy to do that. Red low pressure is below 1 and red high pressure is above 3.

With regard to the earlier encouraging reply, can I just clarify? - I know very little but I THINK there is an expansion vessel inside the boiler but I also have an expension vessel (like a tennis ball) fitted in the cupboard underneath the boiler. Do you think this will be covered by my 'boiler cover' with British Gas?

Thanks for your continuing assistance.

 

[kevplumb]

View media item 14780
shock arrestor

cold water nothing to do with it

 

[JSM]

Kevplumb,

It looks similar to that blue thing you sent - mine is silver but I'm sure that is pretty irrelevant. Do you think it will be covered?

 

[kevplumb]

no but it's not part of the problem

 

[JSM]

Sorry, about this but do you mean it is the internal expansion tank which is the problem?

Thanks again.

 

[twgas]

boiler probs are usually covered but it does depend what contract you have.

 

[JSM]

I'm certainly covered for the boiler but can you confirm that the problem described is likely to be due to the internal expansion tank and not the wee 'tennis ball' underneath?

 

[kevplumb]

yes the heating has nothing to do with the cold water

which is what your"tennis ball" is connected to