current heating is gravity HW and pumped heating - All rads except bathroom
have TRV, and none of the rads are balanced.

There is no tank or room stats at all. A 7day timer is fitted

Current plan (based on improvement gained / ease of installation) is:

a) Leave system as Gravity HW / Add 2 port valve close to boiler to give
independant control the HW.
b) Leave curent timer on system, and set to control control time for HW -
heating always on
c) Add a Danfoss wireless cylinder thermostat to control HW temp (wireless
as wireing between cylinder and boiler would be complex)
d) Add a Danfoss TP7000 Room stat to Hall (Lock existing TRV to full on)
e) Balance all rads (i.e 12deg temp differential)

Am I missing something in my thinking, before I order the parts?

Am I missing something in my thinking, before I order the parts?

1. You may need something to prevent gravity circulation in the CH circuit.
This will depend on circumstances, but could be either a 2 port valve or a
one way valve (with circuit flow set to be against natural convection). It
may not be necessary.

2. Remove the TRV from the roomstat room. Some well meaning person WILL turn
it down.

3. Ensure boiler is safe with valve on the gravity circuit. It may need that
circuit to be free flowing for two reasons. Firstly, it may need somewhere
to dump heat at all times (particularly solid fuel boilers). Secondly, it
may need the circuit to provide a steam outlet/quenching water inlet path.
This would either require careful layout to ensure that the 2 port valve
doesn't block those paths or require the boiler to have an overtemperature
safety cutout and pressure relief valve.

4. Consider pumping the hot water gravity circuit.

Christian.

"Christian McArdle" wrote in message
et...
Am I missing something in my thinking, before I order the parts?

1. You may need something to prevent gravity circulation in the CH
circuit.
This will depend on circumstances, but could be either a 2 port valve or a
one way valve (with circuit flow set to be against natural convection). It
may not be necessary.

Why would you need something in the circuit to prevent gravity circulation
in the CH circuit, if control is added to the HW circuit. I presume that at
the moment, when HW only is running there is already no circulation in the
system? The current system will already be HW only or HW & CH. With a 2
port valve you get the options of HW Only / CH Only / HW & CH

2. Remove the TRV from the roomstat room. Some well meaning person WILL
turn
it down.

Agreed - but would work in the short term. Some TRV can be locked off to
prevent them turning.

"Mark" wrote in message
...
Agreed - but would work in the short term. Some TRV can be locked off to
prevent them turning.

Never met one in a hotel that couldn't be persauded to give a little more
heat in winter.