DHW priority while zoned with circs

russiand

I am a little stumped on how to rig this up. Lochivar knight wall hung, piped primary secondary obviosly. Boilermate tank, and zoned with circs. How do i hook up a Taco SR506 control to not compete with the DHW? Boilermate is hooked up to the Dhw contacts on the boiler and so is its circ. Taco is hooked up to the zone 1 contacts on the Knight. When Dhw is running I cant seem to prevent Taco controlled cirs from running too. How do i rig this up? I have 5 zones on the Taco.. Thanks in advance

russiand

Oops

Just realized Imwas overthinking this one! If i connect another wire from the Boilermate to the Sr 506 priority zone I think I get what I need . Bothe the Lochinvar DHW and sr506s priority zone will be triggered and I will get the desired behavior. Am I on the right track?

Mark Eatherton

The Knight already has relays....

BUT, they are not designed to handle the amperage of 5 pumps running at the same time.



If you set an RIB relay (Functional Devices) with a 120 volt coil to switch power on and off to the SR control, you can use the internal control logic on the boiler to prioritize the DHW call. The DHW call can be done with either a 10K sensor (preferred) or a simple dry contact output. The reason the sensor is preferred is that it allows the very intelligent control logic to modulate the boilers fire power when doing DHW because it can see the reaction of the DHW tank and respond accordingly. Otherwise, if using the switch, it has a tendency to cycle off of the high limit, and doesn't tend to modulate around the real time load.



You would then use the boilers output relay control for the DHW pump, and you can then re-jumper the SR for non prioritized control, and have another spare output zone for future expansion.



You paid for it, you might as well use it.



The space heat output of the boiler should only be used to operate the coil of the relay. THe load must NOT be switched through the boilers SH relays, unless the total amperage of the space heating pumps are less than the amperage rating of the boilers contacts.



HTH



ME

russiand

Still a little confused.

So you mean that I sould use the system pump terminals on the Knight to switch my Taco SR506 on and off in concert with DHW? It sounds like I need another relay to do this, since I am not sure how I can operate only the coil of the SR506 and not the whole box? Thanks again.

p.s. It looks like the latest and greatest SR506-EXP-4 has an additional set of priority driven dry contacts. This sounds like it would solve the issue as well. Unfortunately I have the older SR506

russiand

Still a little confused.

So you mean that I sould use the system pump terminals on the Knight to switch my Taco SR506 on and off in concert with DHW? It sounds like I need another relay to do this, since I am not sure how I can operate only the coil of the SR506 and not the whole box? Thanks again.

p.s. It looks like the latest and greatest SR506-EXP-4 has an additional set of priority driven dry contacts. This sounds like it would solve the issue as well. Unfortunately I have the older SR506

Ironman

Wiring

As Mark said,

Use a relay with a 120v coil such as an RIB (relay in a box). Connect the relay coil to the "system Pump" terminals on the boiler.

Remove the jumper on the SR506 between "ZC" and "ZR". Wire "ZC and "ZR" through the normally open contacts on the RIB relay. This will break power to the pump relays in the SR506 when power is interrupted to "System Pump" terminals in the boiler. Make sure the boiler is configured to only power the "Domestic Pump" during a call for that.



The lights will still come on the SR506 when a zone calls during domestic priority, but there will be no power to its relays to energize the pumps.

russiand

Any chance I can connect system pump output to ZC on SR506

Running a wire from the hot terminal of the system pump on the Knight to the ZC (jumper ZC-ZR removed on the SR506) just operates the control relay on the SR correct? Will this approach work or am I stuck with the RIB purchase?

tnx

Ironman

Relay Needed

You'll need the relay because the micro relay in the Knight's control board can only carry one circ, not five.

Mark Eatherton

A RIB....

is around $25.00.



http://www.google.com/products/catalog?q=RIB+relay&hl=en&client=safari&rls=en&prmd=imvns&um=1&ie=UTF-8&tbm=shop&cid=16431421878356162276&sa=X&ei=1Lw2UIT_LMvvigLaioCQBQ&ved=0CFgQ8gIwAA#ps-sellers



ME

gennady

priority

Priority Operation: When zone 6 is switched to the priority setting

and is actuated, all other zones will stop operation until zone 6 is satisfied.

When zone 6 is not switched to priority, all zones will operate

independently

http://www.taco-hvac.com/uploads/FileLibrary/SR506(102-085).pdf

Ironman

Understood

But if the domestic is piped directly from the boiler and /or a 10k sensor is used, then the control board on the boiler has to control priority.

gennady

duplicate

duplicate

gennady

DHW pump

use system pump terminal x1-2 to power up sr506 and connect DHW pump to DHW pump terminal on the boiler x1-3. when you have a DHW call, 120 sent to power up DHW pump , system pump and boiler pump are out, and when system pump is out, there no power to sr506. You have to pipe DHW pump in boiler side.