Hi Guys and girls, I have a Heatslave 15/19 oil boiler, Of late the over heat button keeps poping out, it seems ok with just the heating on but when i have a shower it pops out, any ideas please !!!
heatslave 15/19 - thermostat overheat button
- Thread starter davegeezzer
- Start date
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Either the divert valve isn't diverting fully to hot water or the plate heat exchanger is becoming blocked up. This means the boiler overheats trying to supply hot water. This will occur if running hot water for a long time like filling a bath.
thanks for your reply, ive maintained the boiler from new servicing it and replacing many parts over the years with guidance from my father in law who was a heating engineer back in the day but now has altziemers so cant help any more, so i like to know the reason behind the problem which you have explained brilliantly, I recently replaced the diverter valve so i reckon i might of possibly fitted it the wrong way round think this would do it !!!
Make sure the heatstore does not have an air pocket in the top.
Is the auto air vent working?
Do you have a good system pressure?
Does it drop quickly?
If the system pressure is low, the pump does not circulate enough and the boiler overheats. If there is air in the heatstore, then the water does notreach the thermostat pocket and the boiler overheats.
Is the auto air vent working?
Do you have a good system pressure?
Does it drop quickly?
If the system pressure is low, the pump does not circulate enough and the boiler overheats. If there is air in the heatstore, then the water does notreach the thermostat pocket and the boiler overheats.
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The pressure is around 1.5, and ive constantly bled the three vents on the boiler ( like a rad valve ) over the last 3 days as well as the radiators. Im not a heat engineer by any means but i know what ive done this shouldnt be happening, what are your thought on the diverter valve on 180 degrees out ? this would mean when the tap is running there wouldnt be enough flow through the valve and so cause it to over heat .
If you have installed the diverter valve back to front then it would give you this symptom, but also you would have permanently hot radiators and no hot water. What diverter is fitted?
the constant bleeding is a concern. Have you bled the pump and the heatstore? If the air vent is stuck, then loosen it on the threads to bleed it. Also, is the expansion vessel failed? If it is full of water, then stands a chance it is k"""""""d. Depress the Schrader valve and if water comes out, replace the vessel.
the constant bleeding is a concern. Have you bled the pump and the heatstore? If the air vent is stuck, then loosen it on the threads to bleed it. Also, is the expansion vessel failed? If it is full of water, then stands a chance it is k"""""""d. Depress the Schrader valve and if water comes out, replace the vessel.
Ok so from what your saying i know i havent put the valve in diverter valve in back to front as the rads only come on with the timer as does the open circuit bathroom towel rad, the diverter valve is probably the 3rd one ive fitted ( in 10/12 yrs ) as i only have the heating on in really cold weather as i have a wood burning stove ( 24/7) which heats my whole bungalow ( if you leave all the internal doors open during the day) obviously this is why i have problems with diveter valves sticking as im in Essex which is a hard water area, The valve comes from Worcester as this is who my father in law worked for ( i have many spares squirreled away ( thanks worcester !! ),
Ive only been trying to bleed the system for 3 days as i thought it was air in the system some where,After tring to bleed the three valves on top of the boiler i always loosen the big screw on the front of the pump incase there is air on the pump, Is one of the 3 bleed screws ontop of the system for the heat store ??,Ive let preasure off the system by turning a plastic knob which lets pressure/ water out the drain through the wall , is this the schrader valve ???.
Thanks for your help !!
The Schrader valve is the car tyre type valve in the expansion vessel. The heatstore is vented by the auto air vent in the top of the boiler.
For someone who has serviced it for 11 years, you appear to know very little abut your boiler. Over the past 10 years I have serviced 25 of these on an estate, and not changed 1 diverter valve, but maybe 20 or 30 synchron motors. As the valve is not exposed to secondary water, the hardness of water is of minimal significance.
For someone who has serviced it for 11 years, you appear to know very little abut your boiler. Over the past 10 years I have serviced 25 of these on an estate, and not changed 1 diverter valve, but maybe 20 or 30 synchron motors. As the valve is not exposed to secondary water, the hardness of water is of minimal significance.
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