Central Heating Pump Too Hot ?

[Secoast]

Just a quick question.

Should a Central heating pump be too hot at any time that you can't rest your hand on it for any length of time.

Cheers

Mark

 

[ShaunCorbs]

Yes as your having 70/80 dc water flowing through

 

[Secoast]

I figured as much, but asked because of this statement (The pump casing is hot)?

Mark

 

[ShaunCorbs]

Normally they either work or they don't

Do all your rads work ?

 

[Harvest Fields]

If you are having problems with rads and the pumpmis red hot then no. But they will get reasonably hot in normal operation.

 

[Secoast]

Everything is working, but the pump hunts when the central heating is on, and is noisier than normal (not an issue when just the hot water is switched on). I'm pretty certain there is no air in the system so I've ordered a new pump.
Just came across that page and thought this might confirm a dodgy pump. Though I did wonder how hot water could pass through the pump without the casing getting reasonably hot. I'll find out for sure when I replace it.

Cheers

Mark

 

[ShaunCorbs]

Do you have one with an air bleed screw ?

 

[Secoast]

Do you have one with an air bleed screw ?

Yes. I've bled this, but don't think any air was trapped. The rads heat to the top, so it appears to be just a pump issue.
The pump is about six years old and is a three speed model (Dab 55/130) that has always been set to the highest speed, don't know what is normal for the life span ?.
It's never run truly silent but is noticeably louder now, and the hunting makes the noise more annoying.

Mark

 

[ShaunCorbs]

Do you have an old flat headed screwdriver?

If so with the pump on, undo the the bleed screw

And push your old screwdriver into the bleed port with moderate pressure does the pump stop ?

If it does pumps had it

 

[Secoast]

I didn't remove the screw to bleed. Is this not going to shoot water everywhere?.

Mark

 

[ShaunCorbs]

No unless there's a major problem

You might get a drip or two but won't be much

 

[Harvest Fields]

Put some kitchen roll underneath as there will be a little bit of water

 

[Secoast]

I'll give it ago tonight. Just out of interest, is the distance between the inlets generally standardised. I've ordered an exact replacement to simplify fitting, but am curious if another make would have been a straight forward option.

Cheers

Mark

 

[ShaunCorbs]

yes they are stnd

 

[Secoast]

OK. Tested last night and there seems to be plenty of torque. I did notice that I can push the spindle back about 5 to 6mm. It returns immediately, so I assume the spindle floats or is sprung along its length.

One thing I did notice during the procedure. I let the system cool down by switching everything off and with the MV port in the CH position there was some heat (warmth) emitted from the MV housing. This is clearly coming from the electrics (motor/electro magnet?). To determine if this is normal I switched the MV into the HW position via the timer, turned everything off and half an hour later no heat.
It seems when the valve port is in the Central heating position, even with everything switched off, the motor/electro magnet? requires power and is generating some heat (nothing excessive). Is that normal?.

Mark

PS. The water from the bleed was not an issue, but more than a few drips. Half filled a paint roller tray after about 3 minutes.