Boilermate II Hot Water Comes Through Hot Then Cold

I had to look at a Gledhill Boilermate II where the customer was complaining that the hot water would come through hot then moments later go cold or just lukewarm. When I first opened the hot tap the water would come through very hot for a few seconds and then reduce to a lukewarm temperature. If I turned the tap off and on again sometimes the water would be hot again at first other times it would continue coming through lukewarm.

The customer originally thought that there was a problem with the boiler but when I arrived at the property the thermal store was up to temperature and the hot water performance was still poor. Increasing the temperature on the Boilermate caused the boiler and pump to run straight away correctly as it should.

I then turned my attention to the Oventrop Blending Valve. These valves are designed to mix cold mains water with the hot water that comes through the thermal store hot water coil to a set temperature. The temperature of the hot water outlets can be adjusted using the plastic knob on top of the valve, turning this adjusts the amount of cold water that mixes with the hot water. In the case of the valve I was looking at, after I turned off the water and removed it I could see that the internal parts of the valve were loose and too much cold water was mixing with the hot.

I replaced the Oventrop Blending Valve with a new one and the hot water was adjusted to the customer's satisfaction. It is important to make sure you have the correct washers for these valves as they tend to fall apart when you remove the old valve.

Disclaimer: The works described in this blog are a record of work undertaken and should not be taken as guaranteed to solve your problem. Work should only be carried out by persons qualified and competent to do so.