I've only a single check valve before my circulating pump (for secondary DHW circuit).
However, I've noticed a problem. When I have my pump turned off (to save heat loss), I find that for a given tap (especially the shower), when the hot water arrives, it is warm rather than hot, and only later reaches the hotter temperature.
I've realised that there is still cold water coming via the secondary circuit which is mixing with the hot, and thus it is only when the secondary circuit is hot (including the primary filling it), that both primary and secondary pipes are hot.
Thus I need a check valve on every spur of the secondary circuit, not just one at the pump, to make sure only the primary supplies each tap (when the pump is off).
I'm wondering what kind of check valve has the lowest cracking pressure? I need to not only consider the low head of the circulation pump, but also the problem that occurs if only one check valve opens thus preventing every part of the secondary circuit from flowing.
For inexpensive valves, I think I have a choice: a) A swing check valve, or b) A universal check valve with the spring removed.
If I have five spurs of 10mm secondary pipe work, I'm thinking a 3/8" swing check valve on each spur should be fine.
What do you reckon?
However, I've noticed a problem. When I have my pump turned off (to save heat loss), I find that for a given tap (especially the shower), when the hot water arrives, it is warm rather than hot, and only later reaches the hotter temperature.
I've realised that there is still cold water coming via the secondary circuit which is mixing with the hot, and thus it is only when the secondary circuit is hot (including the primary filling it), that both primary and secondary pipes are hot.
Thus I need a check valve on every spur of the secondary circuit, not just one at the pump, to make sure only the primary supplies each tap (when the pump is off).
I'm wondering what kind of check valve has the lowest cracking pressure? I need to not only consider the low head of the circulation pump, but also the problem that occurs if only one check valve opens thus preventing every part of the secondary circuit from flowing.
For inexpensive valves, I think I have a choice: a) A swing check valve, or b) A universal check valve with the spring removed.
If I have five spurs of 10mm secondary pipe work, I'm thinking a 3/8" swing check valve on each spur should be fine.
What do you reckon?