Spluttering hot water (1 Viewer)

[Rasputin]

I have a puzzling problem,
I am getting spitting and spluttering from all the mixer taps, but only when using the hot water side presumably due to air in the pipes. Currently I am not heating the water.
After a while the spluttering stops, but will recur when hot water tap is opened again. I cannot see any split or leak in the pipes near the heater (Truma Combi E), so I assume there is something amiss in the heater unit itself.
Any thoughts or suggestions?

 

[Jewellbags]

I had that for a while after descaling the boiler but cleared itself

 

[GeoffnDee]

Could it be that there is a non-return valve in the water supply pipe into the Combi that is faulty/stuck open ?

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[Ian Bosman]

Could be a joint on a push fit pipework system that is leaking slightly

 

[L' Hobo]

I have a puzzling problem,
I am getting spitting and spluttering from all the mixer taps, but only when using the hot water side presumably due to air in the pipes. Currently I am not heating the water.
After a while the spluttering stops, but will recur when hot water tap is opened again. I cannot see any split or leak in the pipes near the heater (Truma Combi E), so I assume there is something amiss in the heater unit itself.
Any thoughts or suggestions?

The problem is certainly air in your hot water side, check all connectors, especially speed-fit push connectors.

 

[Jev88]

You can get a loose joint that under pressure moves and allows air to be pulled into the pipe as opposed to spraying out like a leak.

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[Rasputin]

You can get a loose joint that under pressure moves and allows air to be pulled into the pipe as opposed to spraying out like a leak.

Thanks for all the suggestions, I had thought that if air can get in then water can get out, but will check the connectors.

 

[Petroleumblownapart]

I have a puzzling problem,
I am getting spitting and spluttering from all the mixer taps, but only when using the hot water side presumably due to air in the pipes. Currently I am not heating the water.
After a while the spluttering stops, but will recur when hot water tap is opened again. I cannot see any split or leak in the pipes near the heater (Truma Combi E), so I assume there is something amiss in the heater unit itself.
Any thoughts or suggestions?

It's air being pushed out of the cylinder section in the boiler...... Patience is the cure.... Just turn the hot tap without heating turned on until it stops.... Can take a minute or more. Do this at each hot tap..... and shower head. If it never stops then you have air being pulled into the system before the pump impeller , somewhere.

 

[Pausim]

What type of water pump do you have? With the submersible type you might expect to see a water leak however if you have a pressurised system this might not be the case. The pressure drops between the water tank and the pump and instead of simply drawing water from the tank it can draw air in if there is a leak. One of the problem areas can be the inline filter next to the pump. If the clear cover on the filter is poorly fitting or has been cracked by frost, air can be drawn in. However, this would not explain why only the hot water seems to be affected except perhaps that tiny bubbles might collect together in the hot water tank.

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[John745]

I had a similar problem, spent ages checking, looking, thinking, etc in the end I took the filter off the pump and connected the pipe directly to pump and problem disappeared. What it was the seal on the head of the filter looked OK but was sucking in air from the head of the filter. basically the seal is rubbish.

Hope you find yours as I know how annoying this can be. good luck

 

[Brains]

Double check your cold weather dump valve is not open.

They are designed to automatically open at +5c and dump the water in the boiler.

The boiler contains about 20L of water.
So close the valve, often which involves tuning a knob AND pressing a button (design dependent).

If needed, to keep it closed put a hot water bottle in the area.
(Don't be tempted to use the old 'clothes peg' trick, you can destroy a boiler and end up with a bill that will have a comma in it)

Then ensure you have enough water on board (40L plus)

Then run the hot taps, 20 liters of air needs to come out, which can take a couple of minutes.

And hopefully Robert is the maters frater .....

 

[Rasputin]

It's air being pushed out of the cylinder section in the boiler...... Patience is the cure.... Just turn the hot tap without heating turned on until it stops.... Can take a minute or more. Do this at each hot tap..... and shower head. If it never stops then you have air being pulled into the system before the pump impeller , somewhere.

Yes, it does stop after a while, but comes back next time the tap is opened, with hot. But if air gets in before the impeller, why does it only happen with hot?

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[Pausim]

Yes, it does stop after a while, but comes back next time the tap is opened, with hot. But if air gets in before the impeller, why does it only happen with hot?

You will only have an impeller if you have a submersible pump in which case air entering the system will not be before the pump. If however you have a pressurised system with a pump outside the tank air getting in to the pipe work or filter between the tank and the pump is a possibility. In this case the inline filter cover is the first thing to check.

The Truma Combi boiler has a 10 litre water capacity. There is an elbow fitting on the outlet that contains a valve which allows the air to escape from the cylinder through a small tube which should go to the outside. This valve sometimes does not close properly and leaks water. If you have a submersible pump rather than a pressurised system perhaps air is getting in through this valve.

What type of pump do you have?

 

[Encantado]

I have the exact symptoms as above #13 hot water spluttering but ok after about 10 seconds. and yes its linked to the truma 6E over pressure valve which is passing onto the floor underneath after the water tap is off.. I have been instructed to have this valve replaced [not done yet]
Interestingly you mentioned the fixed filter on the pump - I have not had this filter as it was lost 3 years ago and not replaced yet

 

[Headrush]

Is the water boiling hot? That might cause sputtering through the hot tap.

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[Rasputin]

Is the water boiling hot? That might cause sputtering through the hot tap.

No, heater is not on.

 

[Rasputin]

You will only have an impeller if you have a submersible pump in which case air entering the system will not be before the pump. If however you have a pressurised system with a pump outside the tank air getting in to the pipe work or filter between the tank and the pump is a possibility. In this case the inline filter cover is the first thing to check.

The Truma Combi boiler has a 10 litre water capacity. There is an elbow fitting on the outlet that contains a valve which allows the air to escape from the cylinder through a small tube which should go to the outside. This valve sometimes does not close properly and leaks water. If you have a submersible pump rather than a pressurised system perhaps air is getting in through this valve.

What type of pump do you have?

It’s a submersible pump. I see a white elbow fitting at the red pipe (presumably the hot water outlet). Does this need to be fixed or changed ?

Double check your cold weather dump valve is not open.

They are designed to automatically open at +5c and dump the water in the boiler.

The boiler contains about 20L of water.
So close the valve, often which involves tuning a knob AND pressing a button (design dependent).

If needed, to keep it closed put a hot water bottle in the area.
(Don't be tempted to use the old 'clothes peg' trick, you can destroy a boiler and end up with a bill that will have a comma in it)

Then ensure you have enough water on board (40L plus)

Then run the hot taps, 20 liters of air needs to come out, which can take a couple of minutes.

And hopefully Robert is the maters frater .....

Definately not the cold weather, it’s a hot summer here.

 

[Rasputin]

It’s a submersible pump. I see a white elbow fitting at the red pipe (presumably the hot water outlet). Does this need to be fixed or changed ?

Definately not the cold weather, it’s a hot summer here.

Apologies for the delay, been away to get cambelt done.
Picture of white elbow....

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[Pausim]

I think there is usually a smaller pipe attached to the other outlet at the top of the elbow so that any water that escapes is carried away to the outside. Is there any evidence of leakage here? This elbow looks a bit different to others I have seen so I am not sure and mine has never failed but others have reported problems with them.

 

[L' Hobo]

I think there is usually a smaller pipe attached to the other outlet at the top of the elbow so that any water that escapes is carried away to the outside. Is there any evidence of leakage here? This elbow looks a bit different to others I have seen so I am not sure and mine has never failed but others have reported problems with them.

I must admit, I thought it looked strange as most of the submersible pumps I have seen, never ever had one, went into the top of the tank?

 

[ManTheVan]

We experienced some terrible spluttering from the hot water circuit last year. Eventually, I traced the issue to the water pressure pump which had a small leak in the manifold (it was spurting a tiny bit of water from the black plastic manifold just as it came up to pressure each time). The manifold itself is non-replaceable so I replaced the Shurflo pump and the problem was resolved instantly.

Having removed the original pump, I used some gasket paste to repair the manifold and kept the pump as a spare.

Good luck.

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[Rasputin]

I must admit, I thought it looked strange as most of the submersible pumps I have seen, never ever had one, went into the top of the tank?

The elbow is on the hot water exit pipe from the heater itself, not the pump.

 

[Manic]

Apologies for the delay, been away to get cambelt done.
Picture of white elbow....View attachment 864320

That the boiler vent valve and it should have a pipe going outside.
I’ve had them fail a few times.

 

[Gingernuts]

I had the same problem, replaced the one way non return valve and all sorted

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[Rasputin]

Apparently this is a pressure release valve, not a one way valve, although there is no tube connected to the small outlet and no visible water on the floor. Truma have two different kits to replace this valve depending on the sizes of the pipes. Pricey I have not yet purchased one to try.

 

[Pausim]

The elbow on the hot water outlet at the top of the tank should have a vent tube attached. It is for automatically venting air from the system and probably helps as a breather when draining down. It is closed by the water in the elbow. Sometimes the valve leaks and needs either cleaning or replacing.

 

[autorouter]

I had that problem in my Hymer. The water tank is below the floor, the water heater is above the floor. The non-return valve (NRV) in the submersible pump went faulty, and the water drained back slowly from the water heater into the water tank. The hot taps would splutter every time, for several seconds.

I solved it by cutting the pipe near the tank and fitting a separate NRV. I have since replaced the pump, with its NRV, so my system now has two NRVs.

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[pappajohn]

None return valve at boiler

 

[LithiumConvert]

I had that problem in my Hymer. The water tank is below the floor, the water heater is above the floor. The non-return valve (NRV) in the submersible pump went faulty, and the water drained back slowly from the water heater into the water tank. The hot taps would splutter every time, for several seconds.

I solved it by cutting the pipe near the tank and fitting a separate NRV. I have since replaced the pump, with its NRV, so my system now has two NRVs.

Thank You.

I need to look at that for our Hymer. The hot taps do splutter every time, for several seconds.