Done everything - can't find problem

[markyd1977]

Hi all,

I'm struggling with my central heating........I've had 2 "professionals" out but still have issues......

I have a hot water tank in the cupboard upstairs, header tank in the loft and the boiler in the kitchen downstairs.

When the heating is on for a few hours I get a loud rumbling through the pipes and the header tank back fills.

I've bled the full system, added fernox, refilled the system and bled all the rads again.

However, I still get the rumbling noises, now it happens when the water is on.

The first guy I had out couldn't find any issues, the 2nd guy told me to turn the pump up from 1 to 3 to take the hot water away from the boiler, however this morning the rumbling was back again.

I bled a little air from the nipple valve in the upstairs cupboard this morning.

The header tank is full (not too full).

All the rads heat up (top and bottom).

When I emptied the system, the water was OK so I'm assuming no sludge.

I'm assuming air is getting is as I can hear it gargling but this is where my issues are.....

Is this an air lock, is air getting in from somewhere (if where, how do I locate it).

Any and all suggestions welcome

I thought I'd try on here rather than have someone else come out and guess at what's going on.

Thanks in advance for any answers or suggestions !!!

 

[GavThePlumber]

When did you empty system and did the problem start from then?

 

[markyd1977]

I emptied the system around 3 weeks ago....I had the same issue around 2yrs ago which is why the pump was changed (the engineer said this was the problem).

It only happens in winter, during the summer months both the heating and water is OK.

This recent issue started about 4-5 weeks ago when the heating has been getting used more.

Cheers

 

[gigz]

Header tank should only have about 4" in it. A picture of your pump/valves might help.

 

[TCCHeating]

You say the header tank is back filling, is the water coming into the tank from the vent pipe? (Pumping over)?

It is possible that the noises are coming from a faulty ball valve in the header tank causing vibrations to travel down the cold mains pipe.

 

[markyd1977]

The header tank has about 4" in it however the ballcock is stuck (the water continues to come out even when the tank is full, I've had to switch off the water at the tap and manually fill for the time being) However as I said, the water level looks good...........I'll upload a picture of my pump and valves shortly

Thanks for the responses so far

 

[markyd1977]

Yes, the water is coming from the vent pipe into the header tank.....There is a pipe in the cupboard with the pump in it which is usually cool but when it's back filling, it's roasting hot....

The noise definitely isn't vibrations, the whole house sounds as if it's about to explode if I don't turn the heating off in time

 

[TCCHeating]

Your pumping over problem needs to be sorted asap. Post up some pics of the piping configuration in the airing cupboard

 

[robin7]

I had similar symptoms a couple of years ago - turned out to be the boiler thermostat had failed; leading to the boiler literally boiling the system water which then expanded violently up the vent pipe

I think you need to get a Registered Gas Installer/Boiler Engineer in to fix this (by the way, you haven't mentioned what boiler you have)

 

[markyd1977]

The boiler is an Ideal (not sure what model)

I'm at work just now, I'll post pictures of the pump & valves as well as boiler make/model when I get home.

I suggested the thermostat but the engineer that came out said that wouldn't cause the gurgling in the rads

 

[markyd1977]

Oh, and the boiler was serviced 2 months ago (not sure if they check the thermostat when servicing)

 

[Gasguru]

Sounds like the pipework's partially blocked between the vent pipe and feed pipe (assuming they're separate).

 

[markyd1977]

So...the boiler is an Ideal Classic, probably about 12 years old, I've tried to attached some pics but the file won't load. There is a white 3 way unit if that helps....... I'm not a central heating technician so all suggestions welcome however I don't believe it's the thermostat. I've just come in and switched the heating on and within 30 secs I hear gurgling in the pipes near the pump, however no banging or overflowing so far after 15 mins. I meant to also say, when it does overflow the boiler cuts out with the overheating switch popping out

 

[gigz]

Deffo sounds like a flow/blockage problem. Follow the feed down from the header tank, where it joins the system try a magnet in that area see if it sticks.

 

[markyd1977]

I'll check the feed pipe tomorrow, but when I refilled the system a few weeks ago there were no issues, surely the issue with the feed pipe would have shown up them and ended up with the system not refilling