Heatslave 12/14 replacing water pump?

[fatsober]

Hi all

I'm relitavley familiar with the boiler having watched nearly every part being replaced over the last 3 years- I have a new one coming but thought I might be able to have a go myself rather than shelling out on a call out just to get this one to limp on for a bit. I'm pretty competent but know my limitations. Here's the issue:

1) Boiler fires up when CH/HW selected but no heat to rads or h/w
2) The actuator/divertor moves fine and doesn't stick
3) The flow switch (I think that's what its called) that sits on the top clicks when taps/ch turned on so that seems fine.
4) Pressure is fine and constant
5) So all is well but no HW/CH and there is nothing from the water pump except that it seems ridiculously hot and the overheat reset has activated a couple of times.

So my uneducated guess is that the pump has gone.

1) Is the pump a simple like for like swap or is any specialist knowledge/equipment required to set it up correctly (rate of pumping..pressure or anything?)
2) Could the faulty pump have caused the overheat button to activate in which case the pump is to blame or is the overheating indicative of something else such as the thermostat being on the blink and then causing the pump to fail?

Any advice greatly appreciated and many thanks in advance.

 

[Burnerman]

The water pump spins all the time on this boiler - either pumping water around the radiator circuit or through the heatslave tank itself.....
The pump should have slight vibration when its spinning, and you can take the central screw out and insert a thin screwdriver to check if you like.
It does sound like the pump has gone AWOL so replace like for like, and keep the speed setting the same.
When the system is depressurised, its an excellent chance to check the red expansion vessel too - with its water pipe disconnected, pump air into it to 10 psi or thereabouts.
The flow switch should only click when the domestic hot water is called for.
John

 

[fatsober]

Thanks John

Yes there's absolutely nothing from the pump, no spinning, vibration or anything.

That's great if I can do a like for like swap - one question as I've not done this before where is the speed control/setting? The pump currently is an IDEAL am I right in think the speed setting it the small black dial with I II III marked on? I can't see the same dial on the BOSCH replacement but I'm sure it's there somewhere and the central sliver screw has nothing to do with the speed?

Many thanks for your help so far mate

Geoff

 

[Agile]

You should first check to see if there is 230v at the pump!

If there is then if its not turning so must be faulty. But they usually hum and get warm in most cases! Try switching to other speeds.

See the FAQ for more information on pumps!

Tony

 

[fatsober]

Thanks Tony, missed the FAQ on pumps just taken a look now. I'll see if the pump has power - its not humming or moving but the outer casing is absolutely scorching hot.

 

[Burnerman]

Usually the pump speed is set to III (Fastest), I've found.
The large screw in the centre is for bleeding and checking to see if the pump impeller is spinning.
The heat in the pump could be coming from the boiler (which can't disperse its heat) or the fact that the pump is live but not spinning.
Definitely check for 250v there when the boiler is calling for heat.
John

 

[Boilerman2]

Do NOT attempt to turn off the 2 isolation valves for the pump as they WILL leak and the bottom valve is nightmare to change I usually de-pressurise the boiler, close the auto air vent on the heatstore, REMOVE the oil burner (to prevent it getting wet!) and then remove the pump head 4-4mm allen screws
i then swap just the pump head with a new one I put an old bath towel under the pum to catch about 1-1/2 pints of water that will gurgle out, once the new pump is in and wired simple repressurise, remember to loosen the cap on the auto air vent again check for leaks, if all ok refit the oil burner and test a standard UPS15/60 is the correct pump for this boiler

 

[Burnerman]

....definite words of wisdom
John

 

[Agile]

If the pump is very hot then almost certainly the pump is seized but has power to it.

You MIGHT be able to unseize it see FAQ.

Tony

 

[fatsober]

Thank you all very much for you advice - and words of wisdom I'm confident I'll be able to do it myself so will order a new pump and post how I get on. Really grateful.

As an aside one reason I didn't want to engage the services of my local (big) firm who I've used for 3 years or so is the rather odd approach to 12 month warranty they have. You chaps sound very experienced/knowledgeable in the field so perhaps you can tell me if this is normal...

Never had all the money to buy a new boiler so it's always been a case of make do and mend. Have it serviced every year but have had some very expensive repairs these are the bits I can remember:

Oil Pump (x2)
Flow Switch
Actuator/Divertor
Burner control box
Expansion bottle
Water pump (x3)
Light (spark) sensor
Burner motor (Think that's what it was)
Solenoid (?)

...and a whole host of other bits and bobs along the way...

As it is a combi and we have no alternative source of heat/water and it always breaks in the winter so have always had to pay up.

But the last time the water pump went it was only 3 months after it had been replaced, so I presumed it was under warranty and to be fair so did the engineer. But I was later told that the warranty on replacement parts is only valid from the time of the first replacement and the first repair was 13 months previous. So regardless of the fact that the new pump had only lasted 3 months because the first on lasted 13 the new one was not under warranty. They did the same to me with the oil pump.

I quibbled and quibbled until a solicitors letter arrived, they gave me £10 off as 'goodwill' but this sort of practice can't be right can it..or is it normal? Also at every repair they have swapped out the parts for not like for like so the water pump for example is not a replacement BOSCH but an IDEAL, I'm guessing these are not as good but am not qualified enough to say.

TLDR:

New parts not under warranty

Thanks

Geoff

 

[Burnerman]

Certain parts of the boiler burner do get a hard time..... for example, the moment you turn the hot tap on - even for an instant - the burner goes through its start up procedure which means that the spark igniter in particular has to put up with many stop and starts. They also don't like dripping hot taps because the float switch goes nuts and the burner does likewise! Much better to run the system for long enough for the burner to actually light up (8 sec typical) I find.
As for the parts replacement, well it depends on what time interval you are talking about, and undoubtably some repairers will fit new parts maybe before their due time.
On the other hand, its a boiler that can give an excellent shower when called for!
Good luck with the pump job.
John

 

[Agile]

Pumps usually fail due to dirt in the system. That's causes them to seize up.

Its normal for any part replaced free within a 12 month period to only be covered up to the original 12 month period.

They should have told you about the dirt in the system and I expect they did but you choose not to pay to have it power flushed or whatever they suggested.

The pumps are all made by the same makers but badged by boiler makers with their own name.

Its normal in the industry to fit whatever pump they have with them at the time.

Tony

 

[fatsober]

Morning chaps

I thought I'd follow the advice on here and just check if the pump was seized and could be freed before buying another.

Took it off and it moved free as a bird, no nasty deposits/build ups. Was a bit baffled as thought to have narrowed it down to the pump. Re-pressurised and turned it on just to see...and now it *seems* to be working fine! I wonder if something had caused it to get stuck (as opposed to seized) and just taking it off has solved the problem although as I say there was nothing obvious.

Tony, you 'expect' too much about me being advised about it being power flushed and me choosing not to have it done. None of the engineers have ever suggested this and I've never heard of it until you mentioned it so I'm going to look into it but it sounds like a very sensible idea.

Thanks for all your help and advice guys, fingers crossed it keeps working until the new boiler arrives...although I know this boiler well and something is bound to break soon....

Thanks again

Geoff