Hoping someone can spot something simple.
I have 2 pumps, that I never want to operate at the same time.
In the link I have attached a drawing of my thoughts €¦

http://tinyurl.com/z2eoz9u

Condition 1. Programmer in Timed=OFF
No live to Heating Ctl board, and no power to pump BP. If flow switch
operates, then RLY (after time T) will operate and put power onto pump
SP via connection (2b) €¦ all fine

Condition 2. Programmer in Timed=ON
Provides live to heating controller €¦ and in the event of it calling for
heat will provide a switched live feed from €˜pump and I can use that
to power the boiler pump BP, via RLY connection (1a)
There are a number of thermostats, zone valves etc. all under control of
Heating Control board so can only run pump BP when there is a 'Pump'
live signal.

If the flow switch operates when boiler is making a heat call, I need
pump SP not to operate, as there would be no power to (2b) that
requirement is met

The issue I have is if there is no call for heat and flow switch
operates I need pump SP to run €¦ so I need to get live feed to it at
that point €¦€¦€¦ currently stumped.
Am I missing something that I can achieve given the DPDT contacts in
relay and SPDT in the programmer.
Otherwise I will have to add in another RLY


Ideas welcome.

rick wrote:
Hoping someone can spot something simple.
I have 2 pumps, that I never want to operate at the same time.
In the link I have attached a drawing of my thoughts .

http://tinyurl.com/z2eoz9u

Condition 1. Programmer in Timed=OFF
No live to Heating Ctl board, and no power to pump BP. If flow switch
operates, then RLY (after time T) will operate and put power onto pump
SP via connection (2b) . all fine

Condition 2. Programmer in Timed=ON
Provides live to heating controller . and in the event of it calling
for heat will provide a switched live feed from 'pump ' and I can use
that to power the boiler pump BP, via RLY connection (1a)
There are a number of thermostats, zone valves etc. all under control
of Heating Control board so can only run pump BP when there is a
'Pump' live signal.

If the flow switch operates when boiler is making a heat call, I need
pump SP not to operate, as there would be no power to (2b) that
requirement is met

The issue I have is if there is no call for heat and flow switch
operates I need pump SP to run . so I need to get live feed to it at
that point ... currently stumped.
Am I missing something that I can achieve given the DPDT contacts in
relay and SPDT in the programmer.
Otherwise I will have to add in another RLY


Ideas welcome.

Are you having a back boiler running in conjunction with a conventional CH
boiler perchance?

On 7/11/2016 9:22 PM, Phil L wrote:


Are you having a back boiler running in conjunction with a conventional CH
boiler perchance?


No ... I have added a shunt pump to an existing boiler primary .......
initially just shut off boiler control .. now rewiring so I can put this
via a time switch.

The link below shows original system, and what I am in process of
changing it to .... changes to left of store now in place.

Once relay Q sorted ... will then add the thermostatic mixing valve on
underfloor heating loop.
Evolution of my system. :-)

On 7/11/2016 10:13 PM, rick wrote:
On 7/11/2016 9:22 PM, Phil L wrote:


Are you having a back boiler running in conjunction with a
conventional CH
boiler perchance?


No ... I have added a shunt pump to an existing boiler primary .......
initially just shut off boiler control .. now rewiring so I can put this
via a time switch.

The link below shows original system, and what I am in process of
changing it to .... changes to left of store now in place.

Once relay Q sorted ... will then add the thermostatic mixing valve on
underfloor heating loop.
Evolution of my system. :-)


forgot to add the link:
http://www.4shared.com/office/RtTLBD...store_TMV.html

On 7/11/2016 7:33 PM, rick wrote:

error spotted ... updated diag (blue link added)

same Q on logic though

http://tinyurl.com/zzwd86k

On 11/07/16 23:41, rick wrote:
On 7/11/2016 7:33 PM, rick wrote:

error spotted ... updated diag (blue link added)

same Q on logic though

http://tinyurl.com/zzwd86k



RLY1b can go to permanent live - the logic remains unchanged. In fact
you need that as your flow switch may not be rated to handle the pump.

A CH pump typically takes upto 0.5A with a starting current ten times
that. It's the starting current that kills components.

The rest I'm still looking at.

On 7/11/2016 11:41 PM, rick wrote:
On 7/11/2016 7:33 PM, rick wrote:

error spotted ... updated diag (blue link added)

same Q on logic though

http://tinyurl.com/zzwd86k


(ignore that update - flawed logic) use original link