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Nov 9, 2018
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Member Type
DIY or Homeowner
Good morning,

I'm trying to get an MCZ Hydro-22 pellet stove to provide heating. The stove is operational and is providing hot water to the taps, but it is not supplying the radiators.

Things I have done:

1. Bled radiators
2. Re-pressurised system (all gauges showing 1.5 bar)
3. Set thermostat to 30
4. Checked electricity to pumps (the lights are on in the diode in the switches) and there is heat on both sides of the pumps (Grundfos) - but there are no power lights on the pumps and pressing the button on them doesn't do anything.

I spoke with someone who suggested that the pumps may have gone, or I need to open a valve somewhere in the system. I've tried a number of valves (returning them to their previous positions after a few minutes).

[This system is at my mum's business in the highlands - she's in hospital - and the installer is now out of business and other engineers are hard to come by, so I'm turning to the internet as a final hope before I make an expensive call to an engineer from some distance away]

Any help greatly appreciated, I've put some photos on from the boiler room at the back.

Thanks
Jake

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Is there a programmer / timer?
Is it that on the board near the top under the switch and socket?
Is it set to ON or Auto and is the time correct?

Post a photo if you locate the programmer
 
  • Like
Reactions: Rob Foster
I would look for a 3 way valve not shifting from Dom hot to Dom hot and ch , it’s not rocket science, a local fella can check this dead easy, do not be baffled by cow poo. centralheatking
 
Thanks both for replies - the programme is set to P01 (which from the manual means on pretty much all the time.

I've taken pictures of all programme settings I can find - there is hot water, so I can only assume its doing what its supposed to, but hot water is not entering the central heating loop.

I'm sure it's an easy fix, but we are in the middle of nowhere and getting someone to come look is a big effort

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Ok ,then see if there is a manual override to th three way
Unit, you could try setting it to change back and forth, and I would give it a sharp smack with a wrench , it is probably stuck Chking
And give it a dose of wd40 plenty right down he holes by the lever,
Plenty mind you, let it penetrate for an hour or so smack it again,
Then see what happens , let me know Centralheatking
 
  • Disagree
Reactions: townfanjon
Set them to on and gave them a thwack with a wrench. The lights on the Grundfos pumps came on, but pressure on the guage went up to above 2.

Going to bleed the radiators again.

Also the switches on the honeywells dont feel sprung and aren't locking into the on position. Suppose that means they need replacing?
 
So just to clarify - I spray WD40 into the grey box which has an electrical wire coming from it?
 
Lever is loose, but does not lock into the open position.

The electrics on it seem to be working fine. I can hear and see them changing when I change heating to off / on

Took the electrical unit off. There is very little movement on the valve adjuster (maybe 1/3 turn) does it need to be more than this?

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No, the Grundfos pumps aren't lighting up (although I have seen them light up this morning).

Is there anyway to tell if the valve is in the open position?
 
Should the grundfos pumps be lit up all the time?

The nearest engineer says he can do it in 2 weeks...
 
So if I'm not getting any lights, even when the system should be working and I'm pressing the grey arrow button then its probably an electrical issue to the pumps?
 
Post no. 8 you said when you set them (valves?) to on, the pump light came on?

Did you hear or feel water move around the pipework?

To latch the valve in manual, push the lever across to on, then push it down into the wider part of the slot that's got the tooth like part on it.
Hold there for a second, as the spring tries to reset the valve it should latch on. (to release push lever up to the longer part of the slot.)
Does the pump stay on?
 
Yeah I saw that the lights came on for an unknown reason earlier in the day, but haven't been able to get them to replicate that since.
 
You might have tried his already but turn the heating Sam and off and that lever should spring back. Pull the lever fast towards you and see if the pump
 
Ok ,then see if there is a manual override to th three way
Unit, you could try setting it to change back and forth, and I would give it a sharp smack with a wrench , it is probably stuck Chking
And give it a dose of wd40 plenty right down he holes by the lever,
Plenty mind you, let it penetrate for an hour or so smack it again,
Then see what happens , let me know Centralheatking

You are kidding right?

I take it you know this guy well and are kidding him along? Well I bl00dy hope you are.

Let's just spray a petroleum based fluid into where a freakin electric motor using brushes sits ! Sorry, but what the hell are you thinking Rob? At the very least, WD40 will start attacking the plastic gears. At worst you start a small fire...

Sorry, but that's just bl00dy irresponsible.
 
You are kidding right?

I take it you know this guy well and are kidding him along? Well I bl00dy hope you are.

Let's just spray a petroleum based fluid into where a freakin electric motor using brushes sits ! Sorry, but what the hell are you thinking Rob? At the very least, WD40 will start attacking the plastic gears. At worst you start a small fire...

Sorry, but that's just bl00dy irresponsible.
The unit is probably stuffed anyway so a squirt will not make things any worse , that’s my opinion and what I would do if it was my gaff....centralheatking
 
I didn't end up spraying them - took the covers off and watched them as they switched on/off - both two way valves are working fine by the look of them.

The only thing I cant work out is why the pumps aren't pushing water around. As I said earlier they did light up - but haven't done since. I've been around the place, set the thermostats up/made sure that every switch I can find is set to on - made sure that the return valve on the heating loop is open etc etc.

Completely stumped.
 
I didn't end up spraying them - took the covers off and watched them as they switched on/off - both two way valves are working fine by the look of them.

The only thing I cant work out is why the pumps aren't pushing water around. As I said earlier they did light up - but haven't done since. I've been around the place, set the thermostats up/made sure that every switch I can find is set to on - made sure that the return valve on the heating loop is open etc etc.

Completely stumped.
Ok , we all need to fault find on his one, r u sure the pumps are actually pumping , often when they are bust,seized the impellor head will rotate but no liquid wil be moved , sorry about underlines I do not know how to switch them off

Chk
 
I would and have done and am living proof , but yes for amatures is probably not a best thing to do..my approach is often radical
But can work
Don’t care if your a pro or not. Still shouldn’t spray stuff that you actually cannot see.
 
I didn't end up spraying them - took the covers off and watched them as they switched on/off - both two way valves are working fine by the look of them.

The only thing I cant work out is why the pumps aren't pushing water around. As I said earlier they did light up - but haven't done since. I've been around the place, set the thermostats up/made sure that every switch I can find is set to on - made sure that the return valve on the heating loop is open etc etc.

Completely stumped.
Is there voltage to the pump? When the valves have motored?
 
I cant tell if they're pumping or not. When I press the grey button on the Grundfos pump they dont light up or anything.

Is there any way of telling without a multimeter?
 
They're a fairly elusive bunch around here - soonest I've been given is two weeks.

Probably need to tell them that I want a whole new heating system (which at this point I actually do) and see if that sparks any interest.
 
My take on the problem......

Those grundfos pumps are absolutely Rubbish, they were a quick and late design to get on the modulating pump market. Whip it out !!!!

The leds will be lit, but the actual performance will be far under.
 
Yes, a new grundfos pump. Those alpha 2’s are a poor pump and haven’t got a great life span
 

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