gas boiler problem

Sparkpea

a friend of mine has a baxi combi he boiler and has hot water working no problem but the rads wont heat although its set to do both. its a system boiler so the pressure is at 1 bar in the green area. all rads are on and have been bled. I've not seen the boiler and have told her I'm not that familiar with gas boilers but said i'd ask some questions. I'm wondering if theres valve in the gas boiler thats not opening correctly, similar to the way a motorised valve would work but I'm not sure how the process works in a gas boiler.

Is there anything else she can check herself? When the rads are turned on the boiler temp goes up to 60 degrees then slowly drops back to 25 degrees..

sorry i've limited info from her!

Jedstaff

Sounds like the pump could be stuck but she'd need an rgi to check as it's inside the casing.

JohnnieK

The same pump that circulates around the heating system circulates around the secondary heat exchanger for the hot water so I dont think it's the pump. It could be the diverter valve or flow switch.

Also the boiler may not be getting a call for heat from the external controls ie motorised valve, room stat or programmer/clock.

Sparkpea

Sparkpea wrote: »

a friend of mine has a baxi combi he boiler and has hot water working no problem but the rads wont heat although its set to do both. its a system boiler so the pressure is at 1 bar in the green area. all rads are on and have been bled. I've not seen the boiler and have told her I'm not that familiar with gas boilers but said i'd ask some questions. I'm wondering if theres valve in the gas boiler thats not opening correctly, similar to the way a motorised valve would work but I'm not sure how the process works in a gas boiler.

Is there anything else she can check herself? When the rads are turned on the boiler temp goes up to 60 degrees then slowly drops back to 25 degrees..

sorry i've limited info from her!

If the boiler is firing then dropping off then you could have circulation problems, with a gas boiler it can pulse the heat out if the heat isn't moving out of the heat exchanger quickly enough.

Sparkpea

cheers folks