Cold water tank in the attic overflowing

[GGg]

Hi All,

Looking for some advice. The tank in the attic has been trickling out of the overflow for a few weeks now.

I have an open vented system with a hot water pump (Stuart Turner monsoon twin 3) fitted.

Have already changed the valve and float in the attic. Set it very low but water is above the float. Tested it fine know it shuts off the feed that way.

Also changed the thermostat on hot water cylinder, so tank isn’t getting too hot and venting over.

I do have a shower fitted with mains cold and tank fed hot. (Plumber at the time said it would be fine because hot water is pumped) as well as 3 other mixers in the house with same hot/cold set up.

Looking online could it be the hot water is being overpowered by the cold, with mains then backfilling down the hot water pipe and filling the attic? I can see this can be resolved with a non return valve? And instead of fitting 4 non return valves can I fit one 22mm NRV on the flow from the pump? (Not the feed as this stops any ability to vent)

Thanks and sorry for the long winded post.

 

[GGg]

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

Also if the coil was split would the water in the hot water tank be dirty? As it was relatively clean.

Can the mixers pass if they are off? As this has happened overnight so nothing on.

Thanks again.

 

[Riley]

Yes they can

 

[Riley]

Not always dirty depends on the system

 

[Riley]

If you have isolators on mixer taps you will need to turn them off systematically to work out which one. My bet would be a shower

 

[GGg]

If you have isolators on mixer taps you will need to turn them off systematically to work out which one. My bet would be a shower

Yeah will go around turning off the isolators on each tap and checking to see if the flow has stopped. Hopefully find it that way.

 

[GGg]

No joy. Turned them off one by one. And then turned off the isolation valve on the entire feed on the pump. Still trickling.

 

[Riley]

Let it drop back down to below the overflow

 

[GGg]

I noticed on the hot water pipes on the pump where freezing cold. Like a mains water pipe. Not sure if this is a stupid point to make, but I turned off the mains water and the water going into the tank has now stopped. If the coil was split wouldn’t it drain down the F&E?

 

[Riley]

How many pipes come off the two larger tanks you have a cold feed to the cylinder. Anything else?

 

[GGg]

How many pipes come off the two larger tanks you have a cold feed to the cylinder. Anything else?

Cold feed to cylinder on the one tank. The other tank has a cold feed to the pump for the bath (both hot and cold tank fed)

 

[GGg]

Turned mains water back and and immediately started going back up into the tank. I can’t access shower mixer to isolate but assumed isolating the entire feed off the hot water pump would do it.

 

[Riley]

So it literally feeds the pump?

 

[Riley]

Sorry I’m getting mixed messages with this does the pump do hot and cold water for the whole house or just for one shower. If all the house is pumped then the fault can only be with your kitchen mixer

 

[GGg]

Sorry I’m getting mixed messages with this does the pump do hot and cold water for the whole house or just for one shower

Pump does whole house, hence I thought if I used the isolation valves on the pump it would stop any backfilling mains. But either the isolation valves aren’t turning off fully or im barking up the wrong tree. However I can feel the pipes on the pump they are cold as if mains water is flowing through.

 

[Riley]

Kitchen mixer won’t be pumped

 

[GGg]

Kitchen mixer won’t be pumped

Kitchen mixer is pumped, turns pump on etc.

 

[Riley]

Only on hot, the cold should be straight from the mains

 

[GGg]

Only on hot, the cold should be straight from the mains

Yes. 3 taps and shower are all like that.

 

[GGg]

Only the bath is tank fed hot and cold.

 

[Riley]

Right let’s backtrack as we keep going round in circles here. Any outlet you have that is hot pumped and cold mains could be your culprit and from what you said sounds the only logical explanation