Header tank replacement

[Sunnydays]

Our recently purchased boat has a gravity fed heating system feeding 2 radiators via a Morso squirrel stove. The header tank as the picture shows is a very much 'homemade'  and leaks... so I'm looking to replace it with something more suitable. Any suggestions as to where I start looking would be appreciated. I am not sure re the capacity but I think its approx 20 litres? Thanks in advance.    

[Ex Brummie]

Check the space available, and check against purpose built feed and expansion tanks at your local plumbers merchants. You can the use proprietary connectors. If you are limited to using something homemade, there is no reason why you cannot properly fit normal connectors. With the correct washers and seals you can eliminate such leaks. My own header tank that has been in use for 29 years, is only a polythene waste paper basket. You may find some chandlers sell bespoke moulded units. See Midland Chandlers TT-006 at £40.00.

[PaulJ]

I would change the pipes (why 2 ??) for some decent quality high temperature/ heater hose too as neither of those hoses will last very long should they get a slug of boiling water.

[wobbly ollie]

8 hours ago, Ex Brummie said:

Check the space available, and check against purpose built feed and expansion tanks at your local plumbers merchants. You can the use proprietary connectors. If you are limited to using something homemade, there is no reason why you cannot properly fit normal connectors. With the correct washers and seals you can eliminate such leaks. My own header tank that has been in use for 29 years, is only a polythene waste paper basket. You may find some chandlers sell bespoke moulded units. See Midland Chandlers TT-006 at £40.00.

Thanks. I'll check with local plumbers and Midland as suggested. If not I'll look to improve on the existing design.

8 hours ago, PaulJ said:

I would change the pipes (why 2 ??) for some decent quality high temperature/ heater hose too as neither of those hoses will last very long should they get a slug of boiling water.

Thanks for the reply. Re why 2? I assumed its a flow? Does a header tank not require an inlet and outlet? I guess I  need to do some research into gravity fed systems. 

[Tony Brooks]

The system needs a feed and a vent so a second pipe from heating system into the tank is likely to be the vent to allow steam and air to escape from the system. Feed to a low point vent from a high point. In some boats you may find a third pipe feeding a ballcock in the header tank to keep it topped up. The vent could  be       fitted over the top of the tank in an inverted U.

Your tank seems to be sealed by the "filler cap". That is very dangerous with a solid fuel stove. If it ever runs away and boils I predict the first thing to fail will be the tank or the green hose. You then get sprayed with boiling water and potentially superheated steam. There may be an open vent elsewhere on the system but if not please take the filler cap off before lighting the stove. It may still vent hot water but it cant then explode.

If the tank is pressurising when heated that might be why its leaking.

Edited September 12, 2017 by Tony Brooks

[Jen-in-Wellies]

As Tony says, if it is currently all sealed up, then the expansion of the hot water is pressurising the system and the tank is probably coping by deforming in to more of a sphere than a rectangular shape. This could well be where the leaks are coming from. Those sort of tank connectors that the pipes feed in via are usually pretty good for sealing in to a plastic tank as that is what they are designed for. They are used on domestic plastic water header tanks. The consequences of the tank splitting when hot could be very nasty.

Jen

[Sunnydays]

10 minutes ago, Tony Brooks said:

The system needs a feed and a vent so a second pipe from heating system into the tank is likely to be the vent to allow steam and air to escape from the system. Feed to a low point vent from a high point. In some boats you may find a third pipe feeding a ballcock in the header tank to keep it topped up. The vent could  be       fitted over the top of the tank in an inverted U.

Your tank seems to be sealed by the "filler cap". That is very dangerous with a solid fuel stove. If it ever runs away and boils I predict the first thing to fail will be the tank or the green hose. You then get sprayed with boiling water and potentially superheated steam. There may be an open vent elsewhere on the system but if not please take the filler cap off before lighting the stove. It may still vent hot water but it cant then explode.

If the tank is pressurising when heated that might be why its leaking.

Thanks Tony. What the photo doesn't show is the white cap on tank has a hole approx 2cms to which was attached a peice of hose into a plastic container. So its not pressurised as such. As i say all a bit homemade and I'm sure theres a better option.

4 minutes ago, Jen-in-Wellies said:

As Tony says, if it is currently all sealed up, then the expansion of the hot water is pressurising the system and the tank is probably coping by deforming in to more of a sphere than a rectangular shape. This could well be where the leaks are coming from. Those sort of tank connectors that the pipes feed in via are usually pretty good for sealing in to a plastic tank as that is what they are designed for. They are used on domestic plastic water header tanks. The consequences of the tank splitting when hot could be very nasty.

Jen

Thanks Jen. See comnents to Tony....

[Tony Brooks]

The bottom "tap connector" hose seems to have a service valve on it. That suggests it might be a feed from the domestic water system. If so then in my opinion the green hose shoudl be the "to the system hose" but its too high up the tank. The next question is therefore "where is the  vent pipe/hose?"

It may be the fitter decided that a service valve on the "to the system" pipe is a good idea but why I can't think. There is so  much water in a  gravity system the odd gallon or so extra from the header tank makes no difference in my view.

Where are you? I think I still have a small strong plastic central heating header tank with ball valve in my garage that was fitted to my gravity circulated gas boiler system. It only has a feed pipe to the system because mine vented through the front bulkhead  onto the well deck. You can have it if you can collect from Reading in a couple of weeks time.

[Sunnydays]

Very nice of you to offer Tony. However I think in the first instance I'm going to look at the system in more detail. I think your later comment is right that the service valve is fitted 'to the system pipe' but as I say I'll give it a good look  to see what he's done. (The system definitely works okay as we've had hot rads when the stove is lit).

[Sunnydays]

On 09/12/2017 at 10:31, Tony Brooks said:

The bottom "tap connector" hose seems to have a service valve on it. That suggests it might be a feed from the domestic water system. If so then in my opinion the green hose shoudl be the "to the system hose" but its too high up the tank. The next question is therefore "where is the  vent pipe/hose?"

It may be the fitter decided that a service valve on the "to the system" pipe is a good idea but why I can't think. There is so  much water in a  gravity system the odd gallon or so extra from the header tank makes no difference in my view.

Where are you? I think I still have a small strong plastic central heating header tank with ball valve in my garage that was fitted to my gravity circulated gas boiler system. It only has a feed pipe to the system because mine vented through the front bulkhead  onto the well deck. You can have it if you can collect from Reading in a couple of weeks time.

Thanks for your offer Tony but i removed the tank and resealed the pipes which are no longer leaking. I might replace the tank at some other time in the future. Thanks to those that contributed to my original post