Discuss Warmflow 70/90 combi in the Plumbing Jobs | The Job-board area at PlumbersForums.net

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Devil

O.K I have an issue with this boiler and its driving me mad, it is as follows:

Boiler will heat up the thermal store but will not provide any hot water to the taps. You do get a short burst of hot at first but then it goes tepid at best, the heat exchanger is hot at first but then runs cold, despite the store being hot.
I have changed the blending valve , still nothing doing, dhw pump is fine as I put a new one on just to make sure that wasn't the issue.
Have been told by Warmflow that it could possibly be the flexible holes that come from the main store. Any suggestion from someone who has a bit more experience with this make would be greatly apprieciated.:confused:
 
When you turn on the tap does the heating pump stop, if not check the fow switch.
Makesure the boiler is bled of air, is the plate h exch really hot on one side & cool on other, if so the plate could be blocked.
Maybe it's the hoses if no proof,maybe it's time to try the cheapest option or gut feeling...........
 
taking a guess at it mate it sounds to me like a flow switch, does the boiler fire up when you turn on a hot tap. Could also be a hot temp senser
 
As said above flow switch. Remove it and move it as they have a tendency to stick on these boilers.
 
Cheers for the replies but cant be the flow switch as boiler fires up when hot tap is turned on, at which stage heat exchanger is red hot but it never lasts??????
 
Have had this due to air in pipework,open all manual finger vents placed around thermol store and vent off any air build up
 
surely just by venting this could not be the answer, i will give it a try though but whyy would my red hot heat exchanger suddenly go cold as soon as a hot tap is opened???:eek:
 
Amazingly, I have the exact same problem. I have a 70/90 Warmflow combi oil boiler. My hot water is very hot for a few seconds then turns tepid. The boiler does fire up when the tap is turned on. The local engineer suggested the heat exchanger is blocked, we live in a very hard water area. I had a magnetic scale inhibitor fitted but apparently these arent very good. The polyphosphorus in-line filters are better. My boiler also loses pressure, the engineer siad the pressure vessel is leaking. This boiler is only four years old and has never worked properly since it was installed.
 
Hi Moony,
Do you think we need a new heatexchanger and pressure vessel, the pressure had been dropping but appears to be stable now after the engineer came out over a week ago and adjusted it??
 
id be checking the filter first - and the pressure relief valve to see if its passing (put a placcy bag over it tap it up and see if water is in it the next day or two.

if theyre ok then yeah perhaps the heat exchanger is scaled up and the pressure vessel is losing its charge. but theyre the last things you should be looking at and most expensive to change.
 
okey, thanks for that advice, i'll check that out and let you know how it goes
 
IT WILL BE THE HOSE THAT RUNS FROM THE BOILER THROUGH THE PLATE HEAT EXCHANGER.
They are now a different design but on the older Warmflow combi's they block up, take it off and rod it out job done.
 
Hi
My Warmflow does the same - what hose are you referring to in your note from Jan 2011 ? The heat exchanger has a thermal store feed at the top right hand corner (on the DHW pump line) and a hot water out from the heat exchanger on the top left side to the mixer ; the cold water in is at the bottom left side of the heat exchanger and the water 'out' from heat exchager at bottom right side of the heat exchager I guess back to thermal store.
The mixer valve & flow switch is OK, DHW only for a few seconds ! Any help welcomed given engineers scratching their heads over this - is the Alpha Laval heat exchager blocked by any chance ?

thanks
 
Sorry Lemmy, we have changed our boiler for a Worcester, which is much better. The Warmflows are basically cheap and nasty and not suitable for hard water areas as the hardness of the water corrodes the aluminium heat exchanger unit very rapidly. Our Worcester has a stainless steel one, so much less susceptible to this problem. Shame I didnt know that when I spent £2500 on it !!!
 
If you spent £2500 on it you were ripped off. Warmflows are pants and one of my customers with one always has leaks, and Firebirds are only slightly better. I always choose (in order of preference) Grants / Worcesters / Triancos
 
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