rads not geting hot!!

[mattytheplumber]

hi guys, just need some advise on this one.....

I got called to a job today and when i asked for the heating to come on the boiler fired up and the pipes round the cylinder were all hot and both sides of the pump!! I tried bleeding the rads to try drag any air out the system but this didnt work. the man said he would be happy for us to do a power flush to get rid of this problem and also any sludge in the system. i just want to know if you guys think that the flush would cure the problem.

thank a lot.🙂

 

[adrianfs1]

the powerflush will clean out the system, however i would firstly shut down all radiators bar the closest to the boiler, demand heat from the boiler, that will force the rad to heat up, bleed off this rad then open another thats close to that one, and so on, this will get the system working, then powerflush.

 

[mattytheplumber]

ok many thanks. 😀

 

[philtheflush]

i would also check the pump

 

[tackleburger]

Sounds like the pump to me what's the hot water running of is it gravity?

 

[Avatar]

you can tell if a pump is working as you csan feel it vibrate if it is. If this problem has just occured, and the heating was working ok b4, it is 99% likely to be the pump.

It would only be airlocked if the system had just been drained down (on a combi system).

You havent really given us enough info to id the problem however:

- has work been done recently
- when did the problem occur
- was the system working ok before

All of these are basic questions that you should be asking (and giving us the answers!)

However a powerflush is not going to solve the problem, unless the system has been like this for a long while, or the rads have got colder with time (which I bet they haven't!)

 

[mattytheplumber]

you can tell if a pump is working as you csan feel it vibrate if it is. If this problem has just occured, and the heating was working ok b4, it is 99% likely to be the pump.

It would only be airlocked if the system had just been drained down (on a combi system).

You havent really given us enough info to id the problem however:

- has work been done recently
- when did the problem occur
- was the system working ok before

All of these are basic questions that you should be asking (and giving us the answers!)

However a powerflush is not going to solve the problem, unless the system has been like this for a long while, or the rads have got colder with time (which I bet they haven't!)

The pump is vibrating, the problem has just occured after heating being off over the summer, hasnt been drained down at all. it is not a combi system, it is gravity fed, cylinder and boiler in same cupboard in an upstairs bedroom.

 

[philtheflush]

could it be valve stuck maybe

 

[Avatar]

You can check the motorised valves:

On programmer call for hot water, and check motorised valve lever has slacked off (check the pipes either side for heat)

Do the same on the heating side - does the MOV lever slack when heating is called for? Does the pipework heat up after the MOV (if it is no to both of these then it is time for a new MOV.)

Hope that helps!

 

[mattytheplumber]

the pipework is getting hot after the MOV in heating mode, i never checked it in hot water mode as there is no problem with the hot water. I pulled the lever on the valve in heating mode and it pulled its self back, so i thought this is correct.... am i mistaken??? It just all seems very strange, i just hope its the pump as somebody has told me they've had problems with split blades inside the pump!!!

 

[Avatar]

When the heating is on (ie calling foir heat on the programmer):

1) the pipework after the MOV should heat up

2) the lever should be slack (i.e open)

If the lever is tight and pulls back then it means your are opening it manually (it should not do this when the heating is being called for).

If this is the case, it means your MOV isn't opening (or may be half opening, or even jammed by the sounds of it) when the programmer tells it to . . .

Solve the problem - fit new MOV.

99% certain that this is what is causing the trouble.

You can even just buy a replacement head if it is a good make like honeywell!

 

[Puddle]

When the heating is on (ie calling foir heat on the programmer):

1) the pipework after the MOV should heat up

2) the lever should be slack (i.e open)

If the lever is tight and pulls back then it means your are opening it manually (it should not do this when the heating is being called for).

If this is the case, it means your MOV isn't opening (or may be half opening, or even jammed by the sounds of it) when the programmer tells it to . . .

Solve the problem - fit new MOV.

99% certain that this is what is causing the trouble.

You can even just buy a replacement head if it is a good make like honeywell!

99 red balloons go floating by...more like !

How do you know there is power from the programmer,how do you know room thermostat is operating correctly or how do you know not a loose connection/broken wire

Maybe do the correct tests on programmer,room thermostat,heating motorised valve,with a multi meter to check before we guess at changing things !!

If it is the syncron motor on the motorised valve faulty,just replace motor not complete head

imho

 

[Avatar]

From the syptoms that he is describing, I would be willing to bet it is the MOV.

If everything was working before, then it is highly unlikely that the programmer has suddenly developed a fault . . .

It is highly likely the MOV has.

Unless you want to advise the OP to call in a qualified heating engineer to apply all the tests you want ( I know plumbers who are 30 years plus in the trade, and dont use multimeters . . .)

 

[ferret]

what valve is it? as some after not being used will stick , some just need the head removing and freeing off others will need replacing , I would check for this first then make sure it is in calling mode with stat up full , check for supply to motor and switch to boiler , you can always check the rad circuit by locking the valve in manual open if need be

 

[Avatar]

Let me know if you replace the valve, and wether that solved the problem.

Really i started off as a fast track plumber, but I know prefer it on another forum as a large quanity of posts on this forum are largely ill informed!

I come on to give out help to those who need it!

 

[unguided1]

I am stunned!!!!! rads not getting hot so it must need a power flush!!!!! Do you work for B.G ???? How about doing some simple cheap basic checks as has been suggested, just because a pump is appearing to be working doesnt mean that the impelar might have fallen of or even possibly the motorised valves have packed up could even be as simple as a new room stat or even an air lock,
What is this fascination with power flushes

 

[stevetheplumber]

I am stunned!!!!! rads not getting hot so it must need a power flush!!!!! Do you work for B.G ???? How about doing some simple cheap basic checks as has been suggested, just because a pump is appearing to be working doesnt mean that the impelar might have fallen of or even possibly the motorised valves have packed up could even be as simple as a new room stat or even an air lock,
What is this fascination with power flushes

i often wonder how we ever fixed heating systems before powerflush machines

 

[tackleburger]

It sounds like fully pumped heating with Gravity water primaries. faulty pump would fit description. unless he can tell us categorically that it is "s" plan "Y" plan etc we are guessing. How about this. Is the cylinder above the boiler with pipework coming directly from said boiler?

Probably sorted by now.