Replace Monoflow System with Reverse Return system

icesailor

In my understanding and experience with "I' Series 4-ways, the properly installed valve becomes the bypass AND the ODR control for the system in which it controls. The boiler controls already in place on any boiler do not control the 4-way, the 4-way controls the boiler like it is an additional heating zone. The high mass side with large radiators will have their system water temperature controlled by the ODR control, controlling the valve. The boiler can be any temperature it is set at. The DIP switches on the 4-way head control the boiler water temperature so it doesn't condense. It will never pump cold secondary water into the boiler without mixing it first.

If doing a replacement, and the high mass heating zone already has a circulator piped in, you only need to add another circulator on the secondary side and wire them together. You don't need to use an additional relay. Of course, all situations can be different. Usually, the only wiring connections to the boiler is low voltage.

TRV's are a wonderful idea on old radiators. Until you actually have to go and install all of them. Especially in old antique cribs on the second floor.

Snowmelt

Ocularis, I looked at the link you posted, usboiler.net and saw they had a outdoor reset that "sisters in to the honeywell smart control" I also looked on page 9. That's what I would suggest we do.
ice. I did read your last post, I'm going to think outloud & it's just a thought the "i" valve with the built in outdoor rest would be good when doing individual zones or should I say if you had a combination of high temp and low temp zone. What I'm thinking in my head and for Ocularis case is ( and again I'm thinking out loud) why just reset the zone, why not rest the boiler? Especially since the outdoor reset is plug and play with the honeywell smart control.

Snowmelt

Oops, I reread the post again, maybe for the bypass it would be worth it but I guess it depends on how many zones.

SWEI

The ODR module for the IQ Control alone costs roughly what a small iSeries-R 3-way valve does. That is the best solution, which covers all bases and gives you full reset control (no lower limit on the distribution temp.)

If all you want is basic boiler reset (which will limit you to a ~150˚F minimum supply temp) the Taco SR501-OR-4 will accomplish that for less than half what Burnham wants for the IQ module. I really wish they would back down on that price.

Snowmelt

Ok swei, so say I use the taco sr504, would you also install a calleffi bypass valve with primery secounday, maybe add the calleffi P/S with dirt magnet 5495?

SWEI

I would install a 4-way iSeries-R and perhaps a DirtMag and see how it works. No need for the hydro separator as @icesailor‌ pointed out. You can always add boiler reset later, but the real savings and comfort come from the ODR-controlled mixing.

Ocelaris

I would need a boiler protection too, so I would need a 4 way mixing valve with ODR, like the taco I100T4R-1. I'd rather have a single ECM circulator and zone valves. The Taco ZVC405 zone valve control would kick on the ECM circulator, and send a control to kick on the boiler's TT terminals. Though it's a dry contact, so I supposed I would need to supply it with 24v.

Since I need a separate circulator for the boiler loop, would it make sense to use a ECM motor pump or can i just reuse my existing Taco 00 series pump (I think). But it may be overpowered for just going through the boiler loop? Would there be any benefit to driving an ECM pump in delta T mode in the boiler loop? The 4 way valve is already going to be shut down to the zone's water when the water temp is below 120, I just didn't know if they made smaller pumps for boiler loop applicaitons?

icesailor

@snowmelt:

"" ice. I did read your last post, I'm going to think outloud & it's just a thought the "i" valve with the built in outdoor rest would be good when doing individual zones or should I say if you had a combination of high temp and low temp zone. What I'm thinking in my head and for Ocularis case is ( and again I'm thinking out loud) why just reset the zone, why not rest the boiler? Especially since the outdoor reset is plug and play with the honeywell smart control. ""

For high mass boilers that need any sort of boiler protection, it becomes the Bee's Knees.

If you have an addition with high temperature zones, you take it off the boiler side. If you have an indirect, you don't need to prioritize it. Its already being done by the valve.

The issue was the need for a By-Pass loop, IMO, the valve becomes the By-Pass loop.

In the general scheme of things, and things costing what they do, the I Series valve is one heck of a deal and a big bang for a buck on a large, high mass system. Just for the way it evens out the temperatures in a system.

OBTW, that same valve will do Boiler reset too. Its a lot of good things in one box.

SWEI

The 4-way valve will provide boiler protection. A ΔT pump on the boiler side would be fantastic.

Ocelaris

That's a really cool product, the dirtmag. I didn't realize the ECM motors would collect black iron oxide; but that makes sense. Good video from Caleffi on them.

https://youtube.com/watch?v=4zT74nJoi3g

icesailor

@Ocelaris:

"" I would need a boiler protection too, so I would need a 4 way mixing valve with ODR, like the taco I100T4R-1. I'd rather have a single ECM circulator and zone valves. The Taco ZVC405 zone valve control would kick on the ECM circulator, and send a control to kick on the boiler's TT terminals. Though it's a dry contact, so I supposed I would need to supply it with 24v. ""

The I Series 4-way has the boiler protection already on the valve. 120 degrees for gas boilers and 140 degrees for oil boilers.

It "re-sets" the system water to high mass radiators operating with ODR, and mixes the return water after the boiler water gets above the set point for condensation. For cold start lovers, the boiler runs at cold start, Not until the internal boiler water temperatures get to the set point, will it allow cold water through the boiler.

If you use zone valves on the high side, you use a ZVC 405.

If you tried to balance a old radiator system and put in baseboard that you tried to balance and use low temperature, you could probably run the whole system with the 4-way and the ZVC. You would set the curve to deliver the hottest water needed in the neediest zone.

There is no limit when you play "Fun With Controls".

IMO.

Snowmelt

If we go that far we might as well use boiler cleaner, sentinel cleaner then inhibiter.