Central heating OK but not hot water. Please help! Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[varela]

I have a Glow Worm Boiler 65/80. There is a single heater unit for the dual purpose of CH and domestic water supply, although the hot water for bathroom and kitchen is provided by pumped circulation. There is a Cylinder (23 Gallons). A corrosion inhibitor was added recently to the CH installation. I normally have HW even if the CH is off.
A month ago I noticed there was not hot water, but the CH was OK.
A heating and plumbing engineer came and said the pump needed replacement.
He also installed an emergency electrical heating element to the hot water cylinder. So I had hot water heated by the electrical emergency system as soon as it was installed.
On completing the work the engineer checked that the boiler fired up when we set the CH thermostat at a higher temperature than that of the house. After his departure I noticed all downstairs radiators were hot but not the upstairs. The engineer did not check whether the Central heating hot water system was working, as the cylinder was full of electrically heated hot water. He said it was no way to check the actuator valve. Now that I switched off the electrical emergency hot water, I see that the hot water cylinder and pipes around it are cold: and I am again as when I called the engineer: without hot water.
Please could any one advice me on this matter? I am afraid the engineer has not found the root of this problem. Do you think I should ask him to change the actuator valve? It is anyway to check if it is working? Do you think the problem could be the timer? I have a Drayton dual channel programmer, installed 4 or 5 years ago. It is any way to check this also?
Any advice would be very welcome.

[stoneyboy]

varela,
If you can find the actuator valve it should have a manual operating lever on it - try pushing this to one side with the boiler on and ch + hw also on. If the pipes into the tank get hot then this is one of your problems. The upstairs/downstairs ch problem is likely to be air lock - if your pump has a speed control try turning this up to max and see if this clears the problem.
OR you could get the "engineer" back.
Or you could try a different engineer.
If you are on a maintenance contract with BG get them back quickly it's their problem.
end

[varela]

Thank you Stoneyboy for your reply. The engineer came and manipulated the actuator valve and also added Tower Triple X Universal Cleanser to the system.
I had hot water for a few days only. The water was only tepid after two or three days so I decided to change the thermostat temperature to see if this had any effect. It did: The pipes into the tank went hot and soon after I had hot water, but only if the thermostat is set at above 26C and the CH and Hot water timer switches are continuously on. Strangely though no radiator gets hot now! - Except for the one in the bathroom connected to the hot water.
Yesterday I lowered the thermostat temperature to 15C and immediately the water started to cool down.
Please would you mind advising me again? I cannot understand what is going on.
Do you think I should change the actuator valve? Do you think the cleanser added may have caused a blockage somewhere in the CH pipe?
I would be grateful for your opinion.