Ratio reset outdoor w/ indirect

tombig

I,m trying to figure out a way to lower the temp of one zone from three. I'm installing a Teledyne Laars Jvi225 for........domestic HW, plate type heat exchanger for water/glycol to garage radiant floor, 88K to 1st floor cast iron radiators. Is there a multi zone
controller out there that will allow me to modulate temp. but still have DWH control? I'm looking at the honeywell AQ475 w/ R888 but it should be simpler.And cheaper! All I wan't to do is drop the C.I. temp on mild days. .......I love lower circ. temps on mild days. And so do the H.O.'s
Well?.............. Oh, by the way, the shower in one of the 5 and 1/2 baths is 10.8 gpm. Hence the freakingly huge boiler. I guess I'm a moisthead!

Steve Ebels

You need

An outdoor reset control with domestic H/W priority. Check out Tekmar. Also many boiler manufacturers have their own controls. What are you using to protect the boiler from condensation when the garage slab kicks on? If you haven't bought the boiler yet you might want to consider one that has a staged burner (two firing rates) or a fully modulating burner. You're opening the door for some serious short cycling when that big dog is only running one heating zone. The Viessmann Vitodens does/has all of the above, modulation, O/D reset, DHW priority, no need for any boiler protection. It would thrive on 50* return water.

Do it once, Do it right

Hope this helps

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tombig

Thanks for the comback. The Honeywell looks like it functions the same as the Tekmar. I'm not worried about low return temps because I expect only a 20* split across the water/glycol heat exchanger. A reset control with domestic HW priority will work as I don't think it will matter(much) if the water side of the heat exchanger operates at lower circulating temps in milder weather. I am very worried about short cycling though. With my DHW load greater than heating load a modulating boiler would be ideal. I couldn't pull up any info on the Veissmann.It sounds like a winner (and pricey). I've installed condensing boilers before, but not staged fire. Is it pvc vented? Or a copper boiler that will handle low return temps? I've done a few radiant floor jobs with CI boilers depending on full size bypass and 3way mixers (sparco,taco) to keep return temps up. On cold start ups with all zones calling the return temps stay low for longer than I'd like. I figure it's not much different than starting up an old timer with huge water volume. Am I wrong here? Thanks in advance. TomBig p.s. Does someone make a remote bulb (outdoor) 3way or 4way diverting/mixing valve in 1 or 1&1/4 in.? Sort of like a bypass type TRV. I know it sounds wacky but I like to keep it simple. Thx again.

Steve Ebels

Tom

The Vitodens is variable fire from roughly 25% to full on. It has its own direct vent, balanced flue system,(variable speed inducer) and it is some type of PVC. Just slips together and locks. Uses gasketed joints. This boiler also has its own O/D reset/DHW control packaged and wired right on it. (Think idiot proof installation) The boiler hangs on the wall and has a 316TI Stainless steel heat exchanger. It isn't cheap but you have to consider what this thing will do for you. It comes out not a lot different than a good boiler plus all the controls, especially when installation is factored in.

Careful with those copper fin boilers. The manufactuers tell you that cold return will not hurt the heat exchanger and that is true for the most part. What they don't tell you is that they still condense. I serviced a pair of 985Mbtu Lochinvars in a car wash running with return temps of 110-115*. This was the temp the carwash company set them at. (What do they know about boilers??) These poor things were condensing so bad it was literally raining inside the boiler. The burners had to be cleaned about every 2 weeks and were shot by 6 months.

Happy hydronicing!!

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tombig

s.ebels

I've only used copper for apt. building HW with a storage tank(so far) so thanks for the tip. It was raining with 115* return? Wow?? I've used the Teledyne CB model a couple times. 2&1/2 times the price of a CI boiler. Vents like a 90% furnace and has a condensate drain. All stainless. Nice unit but price is huge factor. I think their model now is the Endurance. It's early enough in the job for changes but the sheet metal contractor already gave me a flue to the roof. (B-vent) I'm still piping the house pre drywall. When the owner finds out how much the 119 gal. storage tank is gonna cost him maybe he'll use the flue for a standard hot water system and let me go nuts with the hydronic heat! I'm in yuppieville Chicago north side where 4000s.f. homes on city lots are going for 1.5 mil. I hate when they give me grief about spending for hydronic heat. Every body wants warm floors and don't want to pay for it. You'd be surprised by how many developers around here sell ferrari homes with yugo forced air systems. Even with forced air they're not zoning.....nothing. Their idea of zoned heating is two seperate systems. Anyway, I'm rambling. Got to call my suppliers about Viessmann. Web searches are getting me nowhere. Knowledge is power. How did ya make out with that American Standard dealie? Again thanks for the tips. Tom

kevin

I don't believe it...

1.5 mil $ for a house and it has only ONE zone for heat!!!!!!!!!!What a shame... Good luck on educating these people and contractors. Got to sell them on the value.kpc

tombig

I'm doing my best to help them see the light. There's more to spend your money on than granite, oak, and 10gpm multi- head showers in room size shower enclosures.