Monoblock freeze protection valve
I can’t find a North American equivalent of a Caleffi IStop.
I could try and order from overseas but would still have to deal with G thread.
There has to be something locally available that will work.
This would be for an air to water monoblock install in Zone 5.
Comments
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Have you contacted Caleffi directly?
Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England0 -
Are you looking for one? What size?
We have some in Milwaukee, we add tailpieces for various connections
Sweat, press, pex, threaded
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream1 -
Thanks hot_rod,
Definitely interested in a set. Preferred would be 1" FNPT on both side but flexible. Looking for two pieces.
Who should I contact?
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Oh wow, a thread that I'm not 2 years too late for! I have also been trying to find a couple of these, ideally either 1" sweat or threaded. The one w/ air temp sensing would be even more ideal as I do plan on running chilled water for AC in the summer, but I'm 95% sure it's not required as the minimum chilled water temp my unit outputs is 7℃, and these valves open at 4℃.
The other options I was able to find are: and But neither of those have the (what I assume to be) vacuum breaker component on top, and AFAICT they're more designed for backflow-preventer antifreeze or something else related but not exactly the same as an air-to-water heatpump installation.
Who should I reach out to @hot_rod?
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Here is the info for ordering the valves. Where are you located? Most wholesalers can order these, they are in the 2024 catalog page 126.
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream0 -
I know you have to keep on good terms with your wholesalers, but it's a real chore to go through that distribution channel when all you need is a few of an obscure part. You sure you can't sell a few on Ebay under an alias?
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Yeah, the odd or low turn parts are culled out of wholesalers these days. They also tend to have a minimum order to get freight incentives, and not all will order one or two parts..
SupplyHouse.com seems to carry some of the unusual parts.
The G thread is on all those valves, so if you find on from a UK, e-bay, or other site, you can get just the tailpieces you need.
That is true of most any Euro part. The US is about the only place that uses NPT, so the adaption is made with nuts and tailpieces. Which also gives you service unions on many of the components.
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream0 -
Hot_rod
Thanks for the link. After some chasing managed to get pricing from local distributor on the part, in the end I ended up ordering from overseas as a pair of them was less then a single unit here (seems to be the Canadian way of pricing).
For others that are looking. The other options readily available are:
Zurn:
Sanco2:
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I don't see a vacuum breaker on that version. Looksm like it intended to protect a vacuum breaker?
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream0 -
Shipping from Europe took a bit, but finally got the iStops installed.
The Amazon NPT to G thread adapters are too long on the G thread side and were bottoming out on the iStop body. Ended up machining them down about 3mm to fit.
Pipes are insulated, have the heat trace on, ready for the winter. I'm thinking of doing a test to see how well it works by pulling the power on the heat pump once we get into real winter conditions.
@hot_rod I don't plan to rely on the vacum breaks at all as I don't want the system to drain down. The idea is to keep the autofeed valve open, so in case of any power loss it will flow city water though the outdoor unit.
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i have been playing with one in my freezer. When it goes off it only dribbles for a few seconds, so not a lot of water loss.
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream0 -
I think those G-thread adapters are meant to be sealed with an o-ring and not tape. That would be why they're bottoming out.
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that is probably a Euro version with straight pipe thread , often they are made up with hemp. A generous accumulation of teflon must work 😅
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream0 -
The G threads on the adapter have a rubber flat wash that they seal on. The issue is the threads on the iStop are very short and the fitting would bottom out on the body of the iStop valve before it got to the washers.
Compared to having to braze metric and imperial fittings together to make an adapter, trimming the adapters was an easy enough fix.
Interesting bit was the valves came with a Daikin part number. I'm guessing it is part of the standard air to water install kit there.
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yes we sell a lot of I stop valves to HP manufacturers
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream0
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