You're confusing a hot water recirculation system to get hot water to the faucets with a hot water boiler hydronic heating system that has PEX in the floors, or walls, etc. The two aren't interchangeable at all.

First question is how is your home heated? Hydronically?

when i had certain questions, i called amba customer service directly and they were very helpful answering questions... the other companies most likely would too over the phone or through email...

Thanks for the replies.

Hollysprings - I am not confusing the two. I am quite aware that we don't have hydronic heating, but we do have a domestic hot water recirculation system, which only certain hydronic towel warmers are compatible with... The Fain model is all stainless, so it is fine, but the non-stainless models can't have any air in the system, which is why closed loop is required.

Busybee3 - I'll give Amba a call. Good idea.

Thanks!

Hudson Reed sells Hydronic towel warmers. Not sure if they are closed or open loop, but you can check their website.

Here is a link that might be useful: TW for a re-circulating hot water system.

Oops, just saw this: Please Note: Our radiators are designed for forced circulation closed loop systems only. They are not compatible with open loop, gravity hot water or steam systems.

Hi Adam! Curious whether or not you figured this problem out? We're having the same issue currently. Myson used to make several open loop towel warmers, but are phasing them out due to low demand. I just called Amba as per your post, but the gentleman I spoke to didn't even know what an open system was!! Arrrrgh! The Runtal Fain unit will work in an open system, but like you said, it's super pricey! Any feedback welcome! :)

Thank you for sharing this experience with Myson. They were on my short list but I won't install something that the manufacturer will not stand behind. After reading this I emailed Myson about the issue and their response was "Dezincification is not covered under the terms of the Myson towel warmer warranty." I'm waiting for an answer from Runtal but based on the communication I've had with them so far I don't think they'll have a clue about this.

For anyone who is interested, the Myson models that can be used with an open system are: Diva, Truva and Elegance (there may be others). None of the warmers that can work in an open system make any claims against de-zincification, as the others do.

As for Amba, many of their towel warmers can be custom ordered in Hydronic but it takes 12-14 weeks, cost more than electric versions, require an additional valve which is a few hundred dollars, and they have no idea about open vs closed. You can send them the one you are interested in and they will ask the manufacturer (apparently Amba is just a middle man).

I'm going to revise my previous statement. According to Myson you can technically install most of their hydronic warmers in an open system. This is a quote from their document here.

"IMPORTANT INFORMATION for HYDRONIC TOWEL WARMER INSTALLATIONS
— Brass constructed towel warmers may be used in an OPEN (i.e. Domestic Hot Water) System in all states except
California and Vermont. Myson brass constructed hydronic Towel Warmers DO NOT MEET the applicable
standards for lead content in CA & VT and therefore they may not be installed on potable water systems in either
state. Aggressive water may affect brass towel warmers adversely and it is recommended that if this condition
occurs that a stainless steel or electric towel warmer be used.
— Stainless steel constructed towel warmers may be used in an OPEN (i.e. Domestic Hot Water) System in all
states.
— Steel constructed towel warmers MUST BE USED on a CLOSED SYSTEM."

My previous statement was based on the fact that Diva, Truva and Elegance specifically say on the product page that they can be used on an open system, whereas the majority of the others do not state this.

Bottom line is that the B31-1 is brass and is susceptible to dezincification. There is no getting around this. However, a stainless steel towel warmer (Diva, Truva, Elegance) cannot suffer from dezincification because it contains no zinc. So I am back on board with getting the Myson towel warmer.

Hi all - for some reason (maybe because this post was so old), I never saw the replies. I apologize! So, we ended up with an all-stainless AMBA unit that took 14 weeks to arrive. We weren't in a rush, so we went for it, and it's awesome. If anyone is still deciding, I am happy to elaborate. It is true that the AMBA reps aren't super helpful on the phone, but because they're based in Atlanta where I live, I just drove there and spoke to a lead rep who was in town from New Zealand (I think) where the model I purchased is built. Either way, it's great! I hope everyone else ended up happy!

Hi Adam Friedlander--after almost 2 years, so you still love your Amba? Which model did you get? Does it have valves so you can turn it off? Thanks!

Hi Adam, I too am I interested in your experience with your Amba. I have had 2 Myson towel warmers start leaking and have just now figured out that they should never have been installed on an open system. I have wasted a lot of money and am looking for a towel warmer to install in our open loop system. Thanks!

Hi all - I love our Amba unit! It still gets hot enough to dry towels after a shower, and doesn't significantly heat the room. Whenever we shut the water off, we do have to bleed out the air, and the water always comes out clear, so there seems to be no issue with rust/debris. We've never had a leak...and I hope I didn't just jinx us! Our model is the Amba Jeeves C Straight.