Central Heating and Hot Water not working

[deewarren]

Hi, can anybody help. Central heating system was installed over 18 months ago. It was installed in a refurbished project, and was working at the time of installtion, and then not used any further, however, i have just tried testing it and to no avail. all rads are full. no air present, even aired how water cylinder. Boiler fires but goes off after a minute. room thermastat turned to maximum. Programmer seems to work ok, selects central heating and hw and clicks ok to on. Water from on top end of boiler is hot, suppose this is the flow, the return is cold. Pump is hot, but water from both sides of pipe are cool. Doesnt seem to have any noise from it, i have tried tapping with hammer. 3 way valve lever moves very freeely down and reamins there, water to all pipes still cool from this. 1st nearest rad is warm, but nothing else. Hot water is tepid, set at 75c. I have opened screw on front of pump and a small amount of water leaked out. Does anybody have a clue what is wrong with it, as i said boiler keeps shutting down. everthing was new, thanks

 

[mickyg]

check pump is spinning. You can access the spindle in the middle. Probably need a towel, a big fla screwdriver and a small flat screwdriver. undo big screw, use towel to catch water. insert small screwdriver and spin motor shaft.

 

[JohnD]

Pump is hot, but water from both sides of pipe are cool.

This indicates that electric power is going to the pump, but water is not flowing through it.

As Mickyg says, start by checking if it spinning - it might be jammed e.g. with old sediment if it was installed on a dirty old system and/or was not properly cleaned and inhibited. If you can get it spinning, then you can give the system a chemical clean, and add inhibitor after washing it out, to prevent a recurrence. This is fairly cheap and easy. If the system has a lot of sludge and sediment in it (e.g. if it is old and has been neglected) it may need more work and expense.

If the pump is already spinning, then the fault might be shortage of water, or a severe blockage. This could include a valve such as a pump valve being closed, but if you say it used to work and has not been fiddled with, then it is more likely a sediment blockage.

I am not a pro.

 

[doitall]

When you say installed 18months ago, can we assume it's been left dry, and only just been filled.

Has the boiler been tested and commissioned.

As the other are saying check the pump is spinning, take the big screw in the center of the pump out and stick a phillips screwdriver in the hole, you will be able to turn the impeller or feel it flying around.

 

[kevplumb]

View media item 667

 

[deewarren]

yes, everybody was correct, after removing cover, the part where you can turn pump around was broken, so i had to remove pump and open, and there i found it was part rusted in and therefore was unable to turn, works fine now. I hate plumbing but with everything else i am ok with, many thanks to all who answered

 

[JohnD]

you really ought to give it a chemical clean now to remove old corrosoin, then after flushing, and add an inhibitor to prevent future corrosion. They will cost you about £15 each. Bale out the old mud from the F&E (if you have one) and wipe it clean before draining to avoid washing more sludge down into the system.