The ST gravity valve ads less resistance to the flow volume of the circulated water compared to a CH non-return valve. Not so the smaller A-rated, sophysticated, intelligent, (and so on) solar pump. No problem for a CH circulation pump, it has enough power to overcome this obstacle. This gravity valve has nearly no resistance to the flow once the pump is turned on.īut a normal (closed looped central heating) non-return valve would 'consume' flow energy, the pump would have to work harder to transport the same amount of water since this 'normal' valve would put a resistane into the plumbing system, it works - even when open - like a break to the volume transported (liter/minute), it would reduce the flow. High rise and extra wide-pipe diameter installations are a different issue as well.īut when we look at the standard ST storage situation we would opt for a standard ST gravity valve. High temperature installations like ST industrial installations are a different issue. But it depends on the parameters, so I extend the excursion :įor ST installations on their own (where the thermal storage tank is directly connected to the solar collector) the solar gravity valve is rcommended - in standard household situations. The first one, the non-return valve used for normal pumped,central heating systems can be used in principle for both issues: ST and central heating. This is the type of non-return valve which the poster Yoshytoshy probably had in mind when being afraid to recommend this for a ST installation.Īnd then there is the gravity non-return valve. The first type is the bog standard type, a valve which will be activated only if the pump kicks in. There are two types of non-return valves:

The nearer to the tank the better.Īnd this is done at point of the highest difference of temperature: the top of the cylinder. So if the warm water thermosyphons from the storage cylinder up to the ST collector and cools down there and consequently returns to the storage cylinder the 'thermal emptying' of the storage tank has to be stopped at the leak: at the hottest point, at the pipe between the hot thermal storage and the cold ST collector. The non-return valve is usually fitted between thermal source and thermal 'waster'.

Plumber tells me that this circuit cannot be tampered with but surely there is a simple solution to a simple detail such as this? I have lagged all the 1' copper myself to minimise loss - Whats the best way to lag the brass joints etc? Something like an insulating wrap or tape would seem to be the way to go. I hate the idea of getting the water temp up to 65 degrees or whatever and then having some of this heat constantly dissapate into my hotpress, attic, walls and floors 24 hours a day 7 days a week. I have noticed that its losing a good bit of water heat overnight and so on. summer) and also condensing boiler otherwise. Its a triple coil cylinder and heated by solar means as of now (ie. Have a Stanley Erin Boiler model with a Gravity flow and all seems to be working well - I did howerver notice that its flow/return circuit is constantly hot weeks after the Stove has last been in use and it seems apparent that the system is working in reverse and now sapping heat from Cylinder?

Wet gravity circuit