Central heating/boiler problem

[LondonAl]

Hi,
I live in a rented flat with a Glowworm Swiftflow 75/80 boiler. We have had several problems with this boiler mostly dure to low pressure. We finally worked out how to increase the pressure and all was fine for a while but we now have another problem.
The pressure guage sits at 0.7 and doesn't change when using hot water. Hot water supply is fine. However when we try to put the Central Heating on the following happens: Pressure guage needle starts quivering madly then rises, the boiler makes a 'whumph' noise like it is firing up, the pressure keeps rising up to 2 and then the pilot light dims and the pressure falls. Once it is below 1 it starts to rise again, reaches 2 and then the pilot light goes out completely. No Central Heating.
Any advice? We're freezing.

 

[nickso]

seized pump probably.

 

[LUNAT]

HI

most likely faulty gauge or too sensitive.

 

[nickso]

HI

most likely faulty gauge or too sensitive.

how does a faulty gauge cut the pilot?

 

[LondonAl]

But what can I do about it? Anything? Or is it a job for the pros?

 

[poolebybirth]

HI

most likely faulty gauge or too sensitive.

how does a faulty gauge cut the pilot?

how would a faulty/sezied pump cut the pilot too though!??

i'm no expert hough obviously!!

 

[gas4you]

The boiler would overheat through lack of flow and if the thermocouple is in series with the overheat it will shut the pilot off.

 

[namsag]

As nickso says pump is not coming on when CH is demanded new pump req these have a grundfoss in them so replace like for like or just change the pump head . Not a hard job for a diyer just drain it down