Tearing my hair out!

[rolyatescort]

do you have any dripping hot water taps,shower mixer dripping or could hot water be seeping into a washing machine or dish washer or any slight water leak on hot water outlet to above.(this will keep boiler in hot water mode and give poor flow to rads)
taps are easy to look at.are they dripping.
next check,turn off main water service valve on inlet to boiler,use a screwdriver in the slot,after 10 mins does the rads get hot,if rads get hot now its the above.ie cold mains water moving through boiler.
if above all correct its probaly your pump or the diverter valve is seized in hot water mode.
pump head is easy to change.

good luck
t

I have checked all taps and all are fine. I have no dishwasher. Same symptoms apply with washer disconnected no obvious leak from washer feed. I will try turning off water feed to boiler while i heat the system prior to my other checks i have to do. Watch this space.

 

[ollski]

Also worth checking the resistance of the ch sensor on the chrome pipe above the pump.

 

[rolyatescort]

Well guys stage one is complete. I have disconnected the furthest rad to use as the low drain point. I then connected a hose to the TRV.

N.B. for all interested in trying this at some point, the threaded flanged bolt that you screw into your radiator that then fastens to the TRV/Lockshield is the same thread as a 'Hozelock' garden tap connector.

Sorry i dont know the correct term for the bolt.

From there it was simply a case of opening the TRV slightly then opening the filling loop on the boiler the same amount to keep constant system pressure whilst still flushing.

The water that ran from the hose was almost clear, no obvious sludge or oxide in the stream. Though i have purchased a flushing agent that i still intend to use.

The interesting point for me was that using this method the feed to that rad got hot in less than a minute where as under normal use it would take hours if at all. This leads me to the conclusion that the pump is shot and that any heat generated to the nearest rad is merely convection/radiation. Would that be a sensible conclusion?

If i am correct then step two is now clearly the replacement of the pump. So next question is it simply a case of undoing the nuts that hold the pump in place and disconnecting the wiring harness? What pumps are a viable alternative to my Myson if i can not locate one. Model numbers/names would be helpful if at all possible.

Thanks in advance

 

[Softus]

...Sorry i dont know the correct term for the bolt.

The term you're probably missing is '3/4" BSP connector'.

The interesting point for me was that using this method the feed to that rad got hot in less than a minute where as under normal use it would take hours if at all. This leads me to the conclusion that the pump is shot and that any heat generated to the nearest rad is merely convection/radiation. Would that be a sensible conclusion?

I can think of three possibilities:
1. The pump is worn/faulty.
2. The rad is blocked.
3. The return from the rad is blocked.

A different pump in very common usage is the Grundfos UPS 15-50. There are others.

 

[rolyatescort]

Thanks for that Softus. The rad appears to be fine, has been flushd with a hosepipe and will heat uniformly if its the only rad switched on.

I will be cleaning the system whilst installing the new pump.

I have looked at the grundofs on plumb world, it seems reasonably priced. Is it as easy to fit as it appears, i.e. 2 nuts and an electrical connection?

 

[ChrisR]

Is it as easy to fit as it appears, i.e. 2 nuts and an electrical connection?

No. There be dragons.
Get a "myson" 6m pump as described above, and remove the 4 allen screws which hold the body of the pump to the impeller housing.

 

[Polly1]

This may have been covered by another reply, but have you checked that your pump isn't set too low? It may need adjusting to pump faster.

 

[rolyatescort]

Is it as easy to fit as it appears, i.e. 2 nuts and an electrical connection?

No. There be dragons.
Get a "myson" 6m pump as described above, and remove the 4 allen screws which hold the body of the pump to the impeller housing.

So i assume from that, that i would take the body of the pump from the new one and put it into the housing of the old one?

 

[Softus]

Is it as easy to fit as it appears, i.e. 2 nuts and an electrical connection?

No. There be dragons.
Get a "myson" 6m pump as described above, and remove the 4 allen screws which hold the body of the pump to the impeller housing.

Just curious Chris - what does this do to the Myson warranty?

 

[kevplumb]

Is it as easy to fit as it appears, i.e. 2 nuts and an electrical connection?

No. There be dragons.
Get a "myson" 6m pump as described above, and remove the 4 allen screws which hold the body of the pump to the impeller housing.

Just curious Chris - what does this do to the Myson warranty?

the phrase "shoemenders " comes to mind

 

[Softus]

Spit it out kev, say what you mean - I can take it...

 

[ChrisR]

So i assume from that, that i would take the body of the pump from the new one and put it into the housing of the old one?

Exactly. If you try to undo the top pump union you can twist the connection to the heat exchanger which could leak, be impossible to get to, etc etc.

 

[Softus]

Ahh - now I get it
Very wise advice from ChrisR, as per usual

 

[rolyatescort]

Hi Guys,

Pump has finally arrived, as per advice above i am going to remove the internals of the new pump to put in the casing of the original pump. I am swapping a CP61 for a CP63.

Stupid question first, i assume the system has to be drained to do this?

Hopefully more sensible question second, the CP61 has 4 allen key bolts holding it in place, the CP63 however only has 2. They appear to be the same centres so the question is can i still swap the 2 over?

Thanks

 

[rolyatescort]

Hi Guys,

Pump is now installed, house is warm, all rads are working and i'm off to put the cleaning fluid in.

Thanks for all your help.