Circulators running after boiler shut down

jalcoplumb_2

I do a lot of Munchkin with the vision 1 package. I run constant circulation with no zoning. I find that by eliminating the zones I eliminate mico-loading and end up with a more efficent system. I can't wait to pair it with one of the new Alph Pro circulators.

Couderay

Circulators running after boiler shut down

I have a Radiant heating system in my house and am using circulators insted of zone valves. Was wondering if they make A zone relay board to keep the circulators running after the demand is met for a few minutes. The system is a codensing boiler with an indirect hot water tank. I have the capabilities to do it for my inderect system but not for my other zones. Also, is this purpose needed?

Brad White_56

Ideally

and in my opinion, radiant systems should be run with constant circulation and fine temperature modulation, not cycled on and off at any demand.

I am not sure of a zone relay board that specifically does that but Tekmar and others do allow a post-firing purge on the boiler circuit at least.

Just a couple of thoughts.

Couderay

When you say constant circulation are you talking on which loop as I have a p/s system

Plumb Bob

All circulators should be on all the time. If you have outdoor reset, the circulators are running much of the time anyway, a little more doesn't make any difference to the electricity bill and is the best way to run your system.

Buster

Can use any kind of "post purge" relay

Couderay

I have a munchkin boiler with a vision one. The zone control is a NIX brand. None of which will allow me to keep the circulators running after the t-stat is satisfied. The zone circulatos that is.I'm definatley open for suggestions

Couderay

Are you asking me Dave, as I don't know if I can

Mike T., Swampeast MO

As Brad mentioned, constant circulation is usually a very good idea when you also have supply temperature reset.

Otherwise you can use a "delay on break" electronic relay. Any good electrical house will stock or at least order. Various "coil" voltages are available (no true relay coil as they're electronic). The dedicated "delay on break" versions are slightly less expensive than those that can be configured for other operations. Most use a standard octal (8-pin) plug-in relay base.

jalcoplumb_2

constant circulation

I have wired circulators to run constant. Just provide 120v and a simple switch. This way you can shut them down in the summer if you like.

John Ketterman

Warning, constant circ does not work if you have more than one zone, with stats calling for heat independently. If one zone calls for heat, all zones will get heat and so the others will overheat.

If you have only one zone, you can use the Munchkin's own built-in variable (0-10 min) postpurge. The delayed-off output is ointended for the primary (boiler) circ; it may have enough power to run two circs, but I can't guarantee it. If not, you will have to run it through a suitable relay such as an RIB (relay-in-box).

Unfortunately, I don't know of any packaged devices that will control multiple zones and provide postpurge in each zone. They really should make such boxes...it's a good idea/

Couderay

Where would this 8 pin plug plug into or could you please be more specific

Plumb Bob

As Mike T says, it is a standard octal relay base. If this makes no sense to you, no offence but you shouldn't consider making such a circuit. You can't really learn from scratch using internet posts.

Brad White_56

That or

instead of a switch, use a 24/120 relay and an outdoor thermostat for warm weather shut-down.

I use a Ralco remote sensor controller (just a thermistor bulb outside) which with the controller all does the same thing.

But as Joseph said, just a simple switch works just fine also.

donmei

I've recently put in a radiant system. We ended up going with the Tekmar TN4 controls. Once I added up the cost of several stand alone systems, it really wasn't much more. On the order of an extra $300 for the TN4.

What I got for that is a system that controls things exactly like you would if you spent your time in the basement constantly twiddling with the boiler.

When the only load is radiant, the boiler temp is pretty much the same as the mix temp. The circulators are almost constantly on with the boiler firing as required. The system varies the temp based on outdoor reset and something called "indoor feedback". i.e. if the circulator is running constantly but can't satisfy the tstats demand, it will up boiler and mix temps above where the outdoor reset curve says it should be. (ex, if someone has a window open)

If a setpoint demand is placed on the system (hydroair as a 2nd stage) it runs the boiler up to a higher temp. We use this only to recover from a setback period. Also, the system brings boiler temp up to make dhw while maintaining the radiant mix temp at a lower level.

It just works so well I could not believe anyone doing any other way if they want some reset functions. I understand the doing a "stone simple" simple system. But once you start to put in any kind of stand alone electronic controls, this really isn't that much more money.