Heating system issues

FreeBear

ThisIsWeird said: The first of the other weird symbols is 'proportional pressure' (or flow). This means it will adjust the pump speed to match actual demand.

But not recommended if there is an automatic bypass valve fitted to the CH system.

ThisIsWeird

Which there probably isn't on such an old boiler and system. But, yes, worth checking.

It's something to ideally end up doing once the system has been checked over, and other issues sorted, such as the DHW stealing the lion's share of the flow. To change that - to restrict the flow to the cylinder - would also benefit from a pump that modulates to suit.

These are sophisticated pumps, and in the majority of cases having them run on a constant speed is wasteful and inefficient.

If the system has an auto by-pass, then chances are that turning the manual speed up to three would also push it open. 

Nothing to lose by a trial on PP - it'll be interesting to see if the rads heat upore quickly, but the DHW would Def need to be off at the same time, or it would simply steal more  hot water!

plumb1_2

The majority of bypass valves on new build are just a 15mm gate valve with the wheel head taken off acting as a lockshield . And shouldn’t be touched once the system is balanced.

Apodemus

Another thought...

Have you checked the temperature of your DHW?  If your tank thermostat had failed, it is possible that the tank is always calling for the three way valve to be open to allow hot water to cycle via the tank.  This would lengthen the heat-up time for the rads (and give you scalding hot water!).

ThisIsWeird

plumb1_2 said:

The majority of bypass valves on new build are just a 15mm gate valve with the wheel head taken off acting as a lockshield . And shouldn’t be touched once the system is balanced.

Hi plumb.

How would one go about reducing the flow to the hot cylinder, so stop it pinching - and returning - hot water from the boiler when both it and Ch are calling at the same time?

greyteam1959

ThisIsWeird said:

plumb1_2 said:

The majority of bypass valves on new build are just a 15mm gate valve with the wheel head taken off acting as a lockshield . And shouldn’t be touched once the system is balanced.

Hi plumb.

How would one go about reducing the flow to the hot cylinder, so stop it pinching - and returning - hot water from the boiler when both it and Ch are calling at the same time?

Is ThisIsWeird a reincarnation of Bendy_House & Jeepers Creepers ??

plumb1_2

greyteam1959 said:

ThisIsWeird said:

plumb1_2 said:

The majority of bypass valves on new build are just a 15mm gate valve with the wheel head taken off acting as a lockshield . And shouldn’t be touched once the system is balanced.

Hi plumb.

How would one go about reducing the flow to the hot cylinder, so stop it pinching - and returning - hot water from the boiler when both it and Ch are calling at the same time?

Is ThisIsWeird a reincarnation of Bendy_House & Jeepers Creepers ??

Does it matter ?

plumb1_2

ThisIsWeird said:

plumb1_2 said:

The majority of bypass valves on new build are just a 15mm gate valve with the wheel head taken off acting as a lockshield . And shouldn’t be touched once the system is balanced.

Hi plumb.

How would one go about reducing the flow to the hot cylinder, so stop it pinching - and returning - hot water from the boiler when both it and Ch are calling at the same time?

Depends how the system is piped up.

FreeBear

ThisIsWeird said:

plumb1_2 said:

The majority of bypass valves on new build are just a 15mm gate valve with the wheel head taken off acting as a lockshield . And shouldn’t be touched once the system is balanced.

How would one go about reducing the flow to the hot cylinder, so stop it pinching - and returning - hot water from the boiler when both it and Ch are calling at the same time?

Most heating systems are set up to give DHW priority over CH. Not sure if any of the "off the shelf" controls will allow the priority to be inverted.... Short of swapping the CH & DHW connections on the timer, but then life gets confusing when you want to programme times.

ThisIsWeird

FreeBear said:

ThisIsWeird said:

plumb1_2 said:

The majority of bypass valves on new build are just a 15mm gate valve with the wheel head taken off acting as a lockshield . And shouldn’t be touched once the system is balanced.

How would one go about reducing the flow to the hot cylinder, so stop it pinching - and returning - hot water from the boiler when both it and Ch are calling at the same time?

Most heating systems are set up to give DHW priority over CH. Not sure if any of the "off the shelf" controls will allow the priority to be inverted.... Short of swapping the CH & DHW connections on the timer, but then life gets confusing when you want to programme times.

I always thought a heat-only/system boiler should be able to supply both CH and DHW at the same time? Certainly those of 15kW output and above - I always thought they were sized to allow for this, tho' I guess there will be times when it would struggle.

PoGee can overcome their particular issue by getting the DHW timed first, earlier in the morn, and then the boiler is free to do only CH before they get up.

I just wondered if the main problem here was not that their boiler couldn't cope with both, but that the ease of flow through the DHW would have the boiler cycling with the hot return, so the CH really didn't have much of a chance. A 'balanced' flow should provide for both to run at the same time, but I don't know if such balancing is normal?