Ideal Response 100 boiler making strange gurgling noises

[ElectRob]

hi i have got a Response 100 boiler and it makes strange gurgling noises when hot water is drawn off in to the bath or shower . This sounds like air but not sure. Any suggestions on a cure. Also the pressure gauge increases rapidly when water is drawn off.
Rob

 

[Agile]

It sounds as if the expansion vessel needs repressurising/replacing. See th FAQ on this site.

The gurgling is a little difficult for me to guess at.

The AAV is at top left ABOVE casing. It might be closed off on the small black plastic plug.

Tony

 

[ElectRob]

Thanks for that. Now would this be the DHW or CH Expansion vessal that needs attention.

 

[Agile]

The CH its on the right and filled with air from the top.

Tony

 

[ElectRob]

Well I did what Agile said and put more pressure into the expansion vessel to the manufactures pressure setting. Praise where praise is due. It did not get rid of the Gurgling noise but it has stopped the erratic movement of the pressure gauge when opening the hot tap. WELL DONE and Thank you AGILE a master in the workings of a response boiler. Now back to the main problem. When I had finished putting more pressure in to the expansion vessel and turned the hot tap on I noticed that the restrictor ball valve on the hot water out, was moving when this gurgling started, I moved the valve to decrease flow rate and the noise stopped, this is until cold water was turned on to get the correct temperature. Could this be a flow rate problem? If so how can I rectify this? If any body as any suggestions it would be very much appreciated.
Thanks Rob

 

[ChrisR]

The boiler should be able to cope with low water flow by cutting down the gas to the burner, There can be problems with sludge round the sensors, or in the heat exchanger generally though which makes them react slowly.

There also may be a flow restrictor inside your boiler - some had them, others not. They fail (almost shut!).
Crucial question - what is the flow rate at the hot tap? Measure it in ltres per minute, with a bucket or similar. Should be around 10.

If you didn't release the pressure from the ch water when you pumped into the expansion vessel, you'll have got a false reading and will probably have to do it again. You can release the water from the small tap up underneath on the right, which they stupidly put a bit of sharp bent metal round!

 

[ElectRob]

Thanks Chris R.
I checked the flow rate with the aid of a bucket and got 11 litres in one minute, and that is with the flow restrictor valve half way closed. So i take it the flow rate is ok. should i take a flow rate of the hot water with the cold running separately, would this make any difference? just a note i live in a hard water area so lime scale is a problem. evan though we have a lime scale reducing thing, could this be the problem like the sludge. Is there a way of getting rid of this sludge? As with the pressure yes i did let water out to release the pressure before pumping up the expansion vessel, and the gauge is now around 1-1.5 bar when hot water is drawn off.

 

[Dan Robinson]

There is no sanctioned way of descaling the heat exchangers of these although we have managed to do a couple with mixed success. I doubt that scale is your problem here though.

 

[Agile]

You should have pressurised the EXV with the drain little tap OPEN and closed it when the pressure was about 0.9 bar, then closed it and repressurised with water to 1.5 Bar ( or 1.7 Bar if it has a LP switch fitted which I think they all do )

It sounds as if the DHW flow adjuster is faulty. I dont know why you are closing it. I suggest you open it to full and that may stop the noise.

Tony Glazier

 

[ChrisR]

A thought - is the Auto Air Vent at the top of the boiler working? AIr stuck in the boiler?