Ideal classic FF250 Boiler Problem

24 Jun 2003
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United Kingdom
I have a Ideal classic FF250 Boiler installed. Its four years old and is part of a sealed system. Its linked to a Megaflow pressure water heater. A couple of days ago the boiler shut down and initially I could n't get it going. However I have now found that if I switch on the heating and turn the room thermostat up the central heating pump kicks in and the boiler ignites and seems to operate ok. Unfortunately if the thermostat is turned down or the heating is switched off at the programmer the boiler again shuts down. So it appears its just the hot water side thats giving me problems.

As far as I'm aware the boiler seems to be ok. I'm open to offers on what the root of the problem maybe. If its simple I could possibly sort it out myself and a ciber beer to those that assist. If not then I'll have to ring round and pay the price :(

I've checked all the usual things electricity supply, thermostat turned up (this is inside the a small plastic casing at the base of the boiler).


Steve F
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As a guess your water temperature stat could be faulty,if it the same stat for hot water and heating then it could be your dirvertor valve.Not sure what sort of system you got,if you have cylinder then I would look at the cylinder temperature stat first.
Thanks for replying. I'm unsure what you mean by a dirvertor valve, however I do have a 2 port motorised valve on the primary flow to the coil within the cylinder.

The stat used for the heating is a room stat in the hallway. I've always believed the hot water temperature was controlled by a small knob (marked 1-6) under a dropdown flap on the actual boiler itself. However I'm beginning to think that somewhere near the cylinder is a thermal control (indirect). I got this info from a installation manual. This I'm going to have to investigate but the diagram suggests there maybe a adjustable thermostat under the cover (when i find it).

Thanks again

Steve F
Normally the cylinder stat is on the outside of the cylinder and what I'm thinking is that the stat might be full of dusts to prevent it working or faulty thinking it already got hot water therefore won't start your pump.The divertor valve is a 3 way port for hot & c/heating in combi boiler.Now I know you got 2 port motorized valve for hot water this could be sticking or wiring to the programmer with bad connection or faulty.Try open up the motorized valve on manual (lever on top then lock it in) then put your water on and see what happen first.
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has anyone got installation instructions for an ff250 ideal classic boiler, 7years old approx.
This won't be anything to do with the boiler.

It is an external control fault.

First thing I would check is the HW 2 port valve head. It sounds as if the microswitch has gone it. Very common fault.

The cylinder stat for the megaflo is built in behind the 'grey door' at the bottom. These are pretty reliable though.

More of a help to you would be to go on the Heatrea web site and get the wiring diagram for the megaflo.

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