Non Combi boiler - low pressure?

Supernova

Alex1983 wrote: »

You most have a blocked cold feed. You could back fill the system as a short term fix. You need the cold feed cut out and repiped or blockage clear to permanently fix.

Anything I could do myself to remove the blockage? British Gas didn't mention this possibility.

Cheers
S

Alex1983

Only if you can cut and rejoin pipework etc. Back fill will be something you could do.

You would need to stick a hose down the vent pipe, the one hooked over the expansion tank and then siphon water down it. Keep doing it while you bleed the system and you'll be able to get it going again for the short term.

Mutton_Geoff

Alex1983 wrote: »

You most have a blocked cold feed. You could back fill the system as a short term fix. You need the cold feed cut out and repiped or blockage clear to permanently fix.

I might be wrong here, but how can the cold feed be blocked if the header tank is full?


There was no point changing the pump if there was no water pressure in the rads. Ignore BG and get a decent practical plumber round.

Alex1983

Mutton_Geoff wrote: »

I might be wrong here, but how can the cold feed be blocked if the header tank is full?


There was no point changing the pump if there was no water pressure in the rads. Ignore BG and get a decent practical plumber round.

The cold feed will be blocked where it joins the heating system, hence the tank full of water and not being able to fill the heating system....it's a common fault on a open system.
I still think the water level is high in the tank and believe because the system is blocked it's been pumping up into the tank which led to the system running dry.

Think your comment about ignoring BG is a bit harsh, you don't understand how a system works but are happy to right off BG, the system will be sludged which caused the blockage and they have quoted to put it right. Expensive or not that's there price, no one is being forced to have it. There breakdown covers have never covered sludge, so what else can they do....

Supernova

Alex1983 wrote: »

Only if you can cut and rejoin pipework etc. Back fill will be something you could do.

You would need to stick a hose down the vent pipe, the one hooked over the expansion tank and then siphon water down it. Keep doing it while you bleed the system and you'll be able to get it going again for the short term.

OK thanks.

I have someone coming tomorrow who quoted £450 for a flush of 5 rads.

The system has never been flushed before, so maybe it's worth it as well as looking at the cold feed if necessary.

S

Alex1983

It certainly won't do any harm, if I'm right and it's blocked then the blockage came from some where, so flushing will cure that. The power flush machine may clear the blockage, they don't normally but it may do.

Mutton_Geoff

Alex1983 wrote: »

Think your comment about ignoring BG is a bit harsh, you don't understand how a system works but are happy to right off BG, the system will be sludged which caused the blockage and they have quoted to put it right. Expensive or not that's there price, no one is being forced to have it. There breakdown covers have never covered sludge, so what else can they do....

I think BG already proved themselves by changing the pump without diagnosing the problem. Plenty of large corporations employ people who are just change modules until the fault has gone. Unfortunately many call themselves "engineers" when they are little more than service technicians.


Unfortunately it's the consumer that loses out. Last time I ever had BG near my house, they had installed a new heating system and not soldered a joint in the loft properly. The first freeze only a week later, the joint popped and my house flooded whilst I was out at work. They told me to claim on my house insurance.


Quite happy to "write off" BG anytime.

Supernova

Alex1983 wrote: »

It certainly won't do any harm, if I'm right and it's blocked then the blockage came from some where, so flushing will cure that. The power flush machine may clear the blockage, they don't normally but it may do.

OK, so some chaps came along and found at least one hard sludge blockage in a pipe behind the diverter and because of the age of the system have decided to treat with gentler chemicals to avoid damaging old radiators.

They will then come back another day to remove the chemicals and clean the radiators.

I haven't found out by how much that ups the cost yet but does this make sense?

Cheers
S

Alex1983

Yes, the cold feed and open vent, where I believe the blockage will be, should be behind the pump/diverter valve.

Did they clear the blockage? I'd be surprised if chemicals clear it.

Supernova

Alex1983 wrote: »

Yes, the cold feed and open vent, where I believe the blockage will be, should be behind the pump/diverter valve.

Did they clear the blockage? I'd be surprised if chemicals clear it.

Removed a portion of pipe and cleared the blockage manually. Took a while to find it as some of the pipework is quite difficult to access in my converted attic.

Heating and water are now piping hot.

They put in some chemicals to break down the rest of the sludge in the system and will Powerflush on Saturday.

Total will be £750 instead of £450 but maybe it's worth it to clean an old system properly? Hopefully the old rads are up to it!

S