Booster pump installed successfully, but now boiler goes to overheat!

[Vitali]

Hi all, need advice as I am an amateur who wanted to improve things but made it worse. Ok, have a duplex apartment with a Baxi solo 2 gas central heating. All working ok but the gravity fed shower upstairs was slow in water pressure, and I found this cheap 0.9 Bar electric booster pump on Amazon and spent half a day installing it myself and to my surprise had no leaks and when switched on it did the job as described--- water pressure increased to have a good quality shower. I installed it on a hot water feed going from hot water tank to shower. When happy with myself I switched the boiler to heat up the water, it started as usual but in 2 min cut off and overheat light came up. First I decided to reset the PCB, so I switched it off for 10 sec. The pipe going out of the boiler was really hot, so just in case I let things cool down and came back to the boiler in 20 min. Started it, it did kick in and then again in 2 min stopped and showed overheat again. So, lads, what it is-- an airlock in the system or is that my pump restricting the water circulation and what do I do? I plan to go all the way back to where I started from disconnecting the pump as we all need a Good shower now. And I only hope it will be the same as it was before.... Thanks in advance!

 

[king of pipes]

Check the circulating pump for your central heating its could be sticking or has failed , fitting a shower pump on your hotwater supply will not casuse your boiler to overheat , your heating pump is the heart of your system it circulates heated water through your radiators and through a coil in your hotwater cylinder from your boiler it is more likely to be your problem , other causes could be a zone valve fault or a electrical problem on the controls cheers kop

 

[Chalked]

Can you post a picture of where you have instead the pump.
Your booster will not affect your boiler.unless! It's been installed on the wrong pipe.

 

[deg]

Where did you get the power to run your pump from? Have you tripped your heating controls or isolated your pump supply or something similar?

 

[Vitali]

Hi, people, thanks for replying, I listened to your advice and concerns and adressed them. Firstly, I double checked all the vents I closed to stop the water when I was fitting the booster pump. And one please closed!!!! I forgot to turn it back on, the one which was going into the bottom of the coil tank. How silly I was I thought turning it back on again. I was sure that was my problem. When I turned the boiler on, it started perfectly but in 2 min cut out, though the overheat led did not light up. In 2 min the boiler started by itself, which was great news, then cut out again in 2 min. I kind of got worried that it cuts out too fast before it was longer intervals... Then OVERHEAT AGAIN! Started touching pipes and circulation pump. The pipe going from the boiler to the pump roasten hot, same as the pump, plus I can hear it running and vibrating. But the pipe going out of the pump is barely warm, so it means that the hot water is not pushed upstairs! I unscrewed the middle of the pump while it running in case there's some air or dirt trapped inside. The water was not shooting out, just fast drops. I took out the middle bolt altogether and again nothing crazy, water not shooting out just dropping out. Took a screwdriver and slightly inserted it in the middle and could feel the rotor/impeller rotating. Switched between the 3 speeds and it behaved adequate as well as dead quiet when off. Does that sounds like a healthy pump? But why then pump is not pushing the hot water further up the pipe? Is that a strong airlock? Expansion tank got hot and full of water when the boiler went to overheat. Even worse, I disconnected the booster pump and put everything back as it was before and still, boiler starts,

works close to 2 minutes and goes to overheat mood. Completely lost...what to do next?

 

[ShaunCorbs]

Turn the pump on does it still overheat ?

 

[Vitali]

I took the power from the socket in the nearest bedroom and ran the cable to install a separate socket with a switch in the hot water tank press. That's the diagram I was using to choose the right hot pipe for the pump.

View attachment 30362

 

[Vitali]

The pump is always on when the boiler is on heating and when it cuts out to overheat the pump still runs and I can't reset the PCB until everything cools down a bit.

 

[ShaunCorbs]

Was it fine / working before you did the works

 

[Vitali]

That's the thing -- all was good.

 

[ShaunCorbs]

Turn your hot water booster pump on does it still overheat? You might need to run a tap

 

[Vitali]

I tried that approach as well. OVERHEAT!

 

[ShaunCorbs]

Time to get a plumber in sorry to say

 

[Vitali]

Now I have the booster pump disconnected altogether but no joy. Could the pump look and sound like running but not pumping? Went to neighbors with the same system. Checked the pipe going out of the circulation pump-- it is hot as it should be. Mine is not!

 

[king of pipes]

Yes the heating pump could be airlocked does it have a screwdriver slot on the front of the pump this can be loosened to remove the air put a cloth under it though also vent all your radiators and high points on your system cheers kop

 

[deg]

Is that gate valve on the bottom of the coil open?

 

[Vitali]

It is open now, yes. How do you check actually if the valve is faulty, only by taking the connection apart?

 

[Chalked]

I think the gate valve may have sheared off.

 

[deg]

It is open now, yes. How do you check actually if the valve is faulty, only by taking the connection apart?

When turning the valve anti clockwise it will just keep turning and turning = broken valve

 

[Vitali]

Then it's in good condition as it stops firm when opened and when closed plus I can hear water flow a bit.

 

[deg]

Try sucking the vent pipe that goes over your small tank in roofspace. Or give it a good blow.

 

[Vitali]

That's a good suggestion, will try everything you say and if no joy, at least I tell to myself---I did all I could and then ring a professional... If you have more ideas, I am up all night working until morning, keep posting! Thank you everyone!

 

[GH77]

Turn on your central heating, does that work? ... did you turn off the valves to your central heating pump when you were working in the airing cupboard? ... i have seen people turn every valve off if they are not sure what is what...

 

[Old Account]

Did you install the pump the right way around ?

 

[Vitali]

I didn't go near the boiler in the first place, I just worked upstairs were the pipes and hot water cylinder is. Turned off 3 valves when installing the pump, was a very straightforward job, then turned back all of them back except for one by my stupid mistake, the one going to the bottom coil of the cylinder. And then when all overheat problems started I double checked and found this valve closed, which is open now but still the problem is there. Pump is installed right I suppose as the water pressure has increased nicely as described by manufacturer.

 

[Vitali]

The boiler starts as it should be: boiler on, fan on, pilot on, burner on. Can see fire burning, all good, but then stops and overheat light comes up and is there until everything cools down and I am able to reset it then.

 

[Old Account]

As mentioned few times before it either your Pump or one of the valves is closed, something restricts the flow therefore it overheats

 

[Vitali]

Can you tell me then what's a not working pump? I understand it is silent, not vibrating, nothing spinning. My one is the opposite and I even unscrewed the middle of it and the impeller is spinning. If some valves are faulty then they would be behaving faulty, never closing to firm end or opening to a full stop. Again the ones I have are working perfectly. I have all the rads switched off now as we need only hot water now. Will opening all rads and bleeding them help solve the issue?

 

[Old Account]

I think @ShaunCorbs has mentioned it earlier you will need an engineer to look at it.
It would be also greatly appreciated if you can let us know what the issue was

 

[Vitali]

Thanks, I will try to blow the pipes in the loft midday today as suggested, and if no luck, will bring a Pro in to solve the problems. Will write back how my saga finished later.

 

[Amateur]

You say "All the rads are switched off now", you should always have 1 open. Someone with more knowledge than myself will be better to explain why. Could this be your problem?

 

[Darren Jackson]

One of the gate valves on the coil or pump could very easily have broken they often do! you think it is all turned on but one could have stayed jammed shut. try loosening the nut & olive on the valve on the side of the pipe that is not getting hot to check if it has opened up properly.

 

[Vitali]

Hi again, did what you told me, took out the valve going to the bottom of the cylinder, (in the picture red top on), first the water shoot out of the coil/cylinder about 3 litres, stopped. Then when I opened the valve another 2 litres came out and then stopped. I thought it should be always under pressure??? Took me the valve completely-- perfectly working valve. Sucked some water/air from the cylinder and the pipe just in case. Put it back. Climbed to the attic and did the same with the vent pipe-- sucked out the water. Went back to the boiler, switched it on, started good as usual after 2 min work- off to overheat again, plus some crazy noises in the pipes this time. Circulation pump hot and working. Completely lost. Time for a professional to clarify things as you all suggest...

 

[Amateur]

.

 

[jajodu]

When you loosened the red gate valve you essentially drained most of the water from the boiler circuit, go to your boiler and check the pressure guage, what does it show? If it's showing empty then use the filling loop to top it up to 1.0 - 1.5 bar. Then try again.