Any gas fitters?

RPWC · 7th November 2019, 07:11

Our Bali netatec has been a pile of $¥1t since new, we have had Bali out about 6 times in the last 12 months for one fault after another, mainly due to no hot water, or heating. Now the pressure drops to rock bottom, so I top it up to within the requisite parameters, within an hour it reaches too high a pressure, drain a little from the radiator to reduce the pressure, I’m talking a couple of eggcup full, and within 30 minutes it drops too low. Any ideas?

macafee2 · 7th November 2019, 09:54

You have a leak. As the heating heats the pressure will increase and then drop as it cools. Does the boiler have a pressure release valve, if this has given up (become weak) it could be allowing water to escape to the drain or the outside

macafee2

another_clean_sheet · 7th November 2019, 10:23

Quote:

Originally Posted by macafee2

You have a leak. As the heating heats the pressure will increase and then drop as it cools. Does the boiler have a pressure release valve, if this has given up (become weak) it could be allowing water to escape to the drain or the outside

macafee2

Not strictly true as being a combi boiler it should have an expansion tank. As the water heats up it pushes water in the expansion tank and as it cools it pushes it back into the system. There will be some pressure variation but nothing like if there was no tank.

macafee2 · 7th November 2019, 12:04

Quote:

Originally Posted by another_clean_sheet

Not strictly true as being a combi boiler it should have an expansion tank. As the water heats up it pushes water in the expansion tank and as it cools it pushes it back into the system. There will be some pressure variation but nothing like if there was no tank.

Are you saying there is no pressure release valve? If there is, why would there be one? My combi had one and it went weak and released water, I don't recall if there was an expansion tank in the boiler or not.

macafee2

stocktake · 7th November 2019, 12:37

All sealed systems will have an expansion vessel. Generally speaking it will have a diaphragm across the middle of it and one side will be air and the other water. If this fails and it all becomes full of water then when the system water is heated it will have no where to expand to (by compressing the air) this will cause the pressure relief valve to open and when the water cools there is low water in the system.

macafee2 · 7th November 2019, 15:28

Quote:

Originally Posted by stocktake

All sealed systems will have an expansion vessel. Generally speaking it will have a diaphragm across the middle of it and one side will be air and the other water. If this fails and it all becomes full of water then when the system water is heated it will have no where to expand to (by compressing the air) this will cause the pressure relief valve to open and when the water cools there is low water in the system.

which takes me back to the question has the pressure release valve failed?
There may of course be an independent leak, which could be a joint out of sight ( a nightmare) or at the radiator valves or a bleed screw not sealing

macafee2

another_clean_sheet · 7th November 2019, 16:42

There will be a pressure relief valve in case the expansion tank is full of water and there is no where for further expansion. This can happen where the diaphragm has split and does not push the water back into the system as the water cools and so you bleed more water into the system thinking you have a water leak when it is all in the expansion tank.

First thing to do is unbolt the expansion tank and shake it to see if there is water in it. If there is then new tank.

If there is not then put a vessel under the pressure valve outlet to see if water is coming out. If there is then pressure valve is faulty - you can see from the gauge at what pressure it is leaking fluid.
If not then you have a leak elsewhere.

RPWC · 7th November 2019, 18:20

Thanks for the replies everyone, I have a care plan with Baxi and they are coming on the 18th. I was just curious as to what it could be.

macafee2 · 7th November 2019, 18:23

Quote:

Originally Posted by another_clean_sheet

There will be a pressure relief valve in case the expansion tank is full of water and there is no where for further expansion. This can happen where the diaphragm has split and does not push the water back into the system as the water cools and so you bleed more water into the system thinking you have a water leak when it is all in the expansion tank.

First thing to do is unbolt the expansion tank and shake it to see if there is water in it. If there is then new tank.

If there is not then put a vessel under the pressure valve outlet to see if water is coming out. If there is then pressure valve is faulty - you can see from the gauge at what pressure it is leaking fluid.
If not then you have a leak elsewhere.

what will happen if you remove the expansion tank? what is to stop water from the system flowing out?

why check the expansion tank before checking where the expansion tank/pressure relief valve flows to?

macafee2

another_clean_sheet · 7th November 2019, 18:28

I did not say disconnect the expansion tank but just unbolt it as it will have flexible pipes to it and so you will be able to see if it has water in it. You can tell by the weight or feel the water sloshing around.
Pressure relief valve will probably open at 2 to 2.5 bar

7th November 2019, 07:11	#1
RPWC This is my second home 75 model car Join Date: Apr 2011 Location: Newcastle upon Tyne Posts: 20,177 Thanks: 4,008 Thanked 5,083 Times in 3,114 Posts	Any gas fitters? Our Bali netatec has been a pile of $¥1t since new, we have had Bali out about 6 times in the last 12 months for one fault after another, mainly due to no hot water, or heating. Now the pressure drops to rock bottom, so I top it up to within the requisite parameters, within an hour it reaches too high a pressure, drain a little from the radiator to reduce the pressure, I’m talking a couple of eggcup full, and within 30 minutes it drops too low. Any ideas? __________________ Cheers. Rich…

7th November 2019, 12:37	#5
stocktake Vis Whiz Rover 75 2.5 auto Saloon Join Date: Jun 2007 Location: LEEDS Posts: 20,590 Thanks: 2,057 Thanked 3,056 Times in 1,621 Posts	All sealed systems will have an expansion vessel. Generally speaking it will have a diaphragm across the middle of it and one side will be air and the other water. If this fails and it all becomes full of water then when the system water is heated it will have no where to expand to (by compressing the air) this will cause the pressure relief valve to open and when the water cools there is low water in the system. __________________ Dave... Lost a few stones and a Gall Bladder and part of a bile duct and all of my dignity in the suppository incident

7th November 2019, 18:20	#8
RPWC This is my second home 75 model car Join Date: Apr 2011 Location: Newcastle upon Tyne Posts: 20,177 Thanks: 4,008 Thanked 5,083 Times in 3,114 Posts	Thanks for the replies everyone, I have a care plan with Baxi and they are coming on the 18th. I was just curious as to what it could be. __________________ Cheers. Rich…

7th November 2019, 18:28	#10
another_clean_sheet Posted a thing or two Rover 75 CDTI Tourer Join Date: Nov 2014 Location: Great Bardfield, nr Braintree Posts: 1,414 Thanks: 303 Thanked 436 Times in 317 Posts	I did not say disconnect the expansion tank but just unbolt it as it will have flexible pipes to it and so you will be able to see if it has water in it. You can tell by the weight or feel the water sloshing around. Pressure relief valve will probably open at 2 to 2.5 bar Last edited by another_clean_sheet; 7th November 2019 at 18:30..

7th November 2019, 09:54	#2
macafee2 This is my second home Rover 75 Saloon & Tourer Join Date: Sep 2012 Location: Lincoln Posts: 14,928 Thanks: 1,630 Thanked 3,032 Times in 2,181 Posts	You have a leak. As the heating heats the pressure will increase and then drop as it cools. Does the boiler have a pressure release valve, if this has given up (become weak) it could be allowing water to escape to the drain or the outside macafee2

7th November 2019, 16:42	#7
another_clean_sheet Posted a thing or two Rover 75 CDTI Tourer Join Date: Nov 2014 Location: Great Bardfield, nr Braintree Posts: 1,414 Thanks: 303 Thanked 436 Times in 317 Posts	There will be a pressure relief valve in case the expansion tank is full of water and there is no where for further expansion. This can happen where the diaphragm has split and does not push the water back into the system as the water cools and so you bleed more water into the system thinking you have a water leak when it is all in the expansion tank. First thing to do is unbolt the expansion tank and shake it to see if there is water in it. If there is then new tank. If there is not then put a vessel under the pressure valve outlet to see if water is coming out. If there is then pressure valve is faulty - you can see from the gauge at what pressure it is leaking fluid. If not then you have a leak elsewhere.