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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.
 
Positive head or neg head pump ?
 
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.

It can be yes, a customer had a tap fitted and another plumber had changed the float valve twice. Turned out it was backfilling the cwsc (cold tank) and overflowing. I advised he fit check valves or change the tap.
 
It can be yes, a customer had a tap fitted and another plumber had changed the float valve twice. Turned out it was backfilling the cwsc (cold tank) and overflowing. I advised he fit check valves or change the tap.

If you want to check this then try and put your hand in the tank and feel where the cold feeds the cylinder
 
Ok thanks for the responses. Will try the feed later, if it is this, will one check valve suffice (on the outlet on the pump) or will I need one installed at each mixer?
 
Ok thanks for the responses. Will try the feed later, if it is this, will one check valve suffice (on the outlet on the pump) or will I need one installed at each mixer?
does the pump do all hot in the house
 
Is your smaller f&e tank above or below the larger cold water tank
 
If the level of the f&e is above the cwsc then if the coil is split the two will try and level out.
 
That’s what I just said?? If the f&e is higher than the cwsc then if the coil is split then the water levels in the two tanks will try and level out
 
The test is, is the f&e water level higher than that in the cwsc
 
So. Sat in the attic whilst the mixer taps where tested. Felt the feed at the bottom of the cw tank and it was sucking the water out quite powerfully, nothing being pressed back up?

The valve has now settled and the water is the correct level.

But in a day or so it will be overflowing again. I’m completely baffled. Picture of the F&E tank just in case I’m missing something obvious.

EA084DBB-C5D5-4C3D-BA80-228951815680.jpeg
 
Where’s the f&e tank? Or is that the f&e tank?? I think you’re missing my point where is it in comparison to the cwsc
 
That’s the F&E tank. Which is married to the CWSC.
I checked the levels in both of them and the F&E doesn’t look higher.
 
Can we get a pic showing both tanks side on? “married to”?? I think you’ve missed the point. It may not be the case
 
Think it’s the coil. Can see water going onto the CWSC when the hot water is turned on to heat up. (Nothing to do with mixer) tried to show a video but it won’t upload. Is that what would happen? The feed pipe down to the bottom of the tank is also getting warm.
 
Can’t really see the levels there. I’m guessing the water level in the f&e is lower though
 
Think it’s the coil. Can see water going onto the CWSC when the hot water is turned on to heat up. (Nothing to do with mixer) tried to show a video but it won’t upload. Is that what would happen? The feed pipe down to the bottom of the tank is also getting warm.
Potentially but keep in mind that that pipe will also deal with expansion so it is likely to be warm
 
The 22mm pipe from the bottom of the bigger cold water tank. That’s the water that’s dribbling through on the picture.

882A535B-740D-416E-9BA1-30337B1912BB.jpeg
 
If you sit up there long enough the smaller f&e tank should start to fill if the water level is indeed higher the other alternative is to shut off the pipes to the pump so there’s no way that water can be coming from anywhere else
 
I’ve turned the hot water pump off. It’s still filling in the bigger tank, which I guess would then fill the smaller tank. But why/how is water going up that pipe?
 
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
 
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.
 
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
 
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.
 
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
 
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.
 

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