Cold water tank in the attic overflowing

[GGg]

The small tank will fill your central heating the big tank fills your cylinder. Assuming it’s piped correctly the only place these to waters come close is in the coil in the cylinder, central heating water inside, domestic hot water outside. There could be a small pinhole in your coil meaning that when it heats and expands water from the smaller tank is able to pass into the domestic hot water. This then effectively makes it all one circuit no longer separate so the two tanks in the loft will try and achieve the same water level. This will only be the case though if the water level in the smaller tank is higher than that in the larger tank otherwise the same would happen only in reverse

Ah sorry I thought it was normal but maybe my system is different. I have 3 tanks. The two I’ve shown are hot water. There’s a smaller tank again that feeds the CH.

 

[Riley]

Yes that will be the f&e is that above the other two tanks. It’s likely a second tank was installed to cope with the pump demand

 

[GGg]

I’ll go back up tomorrow to check but I think that tank is a lot lower down. Thanks for all your responses and help. However I assume the water coming back up into the CW tank is the issue as it’s being pushed back up the feed. Will take some
More pictures tomorrow. Thanks again.

 

[Riley]

Which could be the case if the f&e water level is higher than the other two tanks. If the coil has split and the f&e is higher then the water will of course come back up the feed pipe. I mean this in the nicest way mate but I think you might need a pro in. If you find the problem I’m not sure what you intend to do

 

[GGg]

Which could be the case if the f&e water level is higher than the other two tanks. If the coil has split and the f&e is higher then the water will of course come back up the feed pipe. I mean this in the nicest way mate but I think you might need a pro in. If you find the problem I’m not sure what you intend to do

Tbh I’ve had plumbers in for the last 4 weeks, changed the two way valves, cylinder stat, ball valve etc and now stating it was my hot water pump.

So I’ve had enough of being fobbed off and wanted a decision on what was wrong so I could then understand and agree/disagree with the next plumber who comes in. If it’s the cylinder then I’ll get someone in to change it, just wanted to diagnose it correctly. As all they seem to be doing is winging it.

I appreciate your comments on getting a pro in, no offence taken I’m an accountant not a plumber.

 

[Riley]

Thank you we are happy to help but likewise we don’t want to see someone flood their house. Do you understand the science of what I was trying to explain

 

[GGg]

Thank you we are happy to help but likewise we don’t want to see someone flood their house. Do you understand the science of what I was trying to explain

Yeah I get it. If the F&E is higher than those two then it will try to level itself out. But the F&E tank is only a small 10 gallon tank so I don’t think it’s higher than that big tank. However I will check.

 

[Riley]

The water level is the key factor not the actual size of the tank

 

[GGg]

The water level is the key factor not the actual size of the tank

This is what a meant by small. It isn’t possible for the CH tank level to be higher than the other two. Woke up this morning and the tanks are full again. And the CWSC is warm with the feed pipe very hot to touch.

 

[Riley]

Ok then it’s impossible to tell from the angle of your pics the levels. That will be down to you. As long as the water in the f&e is lower than that in the larger tanks then you can rule out split coil. Only logical other fault then would be one of your mixers passing