Condensing Cast Iron?

L'town radiant

Has anyone seen one of these Ray Boilers Operating? ( www.knowsomethingmore.com ). They suggest that the force of the down-draft combustion blower will clear the condensate off of the boiler section. I just can't imagine that that would eliminate all of the corrosive elements from the cast iron. It sure is a slick looking thing though.

Pete Caruso_2

full condensing for years and years

Hello L'Town,

Yep, I've seen rAy run. (I'm rAy's sales manager.)

I was very skeptical about cast iron and condensate, and did not take my new job until I'd heard from contractors who'd had hands on rAy's "big brother" the cast-iron condensing Hydrotherm KN boiler for several years.

The word from them is that the KN, put to hard use on mixed snow-melt, radiant space-heat and DHW in ski country looks almost brand new inside, on the casting itself.

Sure, the down-fired burner does push condensate off of the face of the cast-iron heat exchanger in rAy, but for my money, what really gives me full confidence in rAy's durability is two other facts:

1) The metal thickness of the commercial-grade cast iron is TWICE as thick as is required by code for a new boiler with its pressure rating (working pressure up to 100 PSI) and

2) Mestek had an independant third-party lab torture-test the heat exchanger in the condensing mode. Based on the amount of iron that was dissolved by the condensate, it should be almost 40 years in the most demanding applications before the heat exchanger has lost enough metal to be at the code minimum for a NEW boiler!

Remember that every cast iron boiler out there condenses on cold start up every time. Cast has been seeing condensate for a long time. Cast iron doesn't last forever, it just lasts, and lasts and lasts if it is good quality to start with.

Let me know if you have any other questions.

THANKS!

Pete Caruso
rAy National Sales Manager
Mestek, Inc.
pcaruso@mestek.com

Brad White_185

From a previous thread, if I may...

Date: April 22, 2008 05:38 AM
Author: Brad White (bewhite-at-rcn-dot-com)
Subject: Hydrotherm KN Series

The Ray is to my understanding, the offspring of the Ken Cohen-developed Hydrotherm KN boiler. Kevin is correct, the castings are thicker and that is the heart of it.

When these boilers were substituted on a project in our office we went to work kicking the tires and met with the inventor (Ken Cohen from which "KN" is derived.) The notion of CI and condensing was an anathema to our thinking as with most of you.

The thickness is sacrificial, such that after 30 years of operation, the wall thickness is still within ASME tolerances.

The "top-down" combustion path continuously combs the exchanger surfaces downward to minimize re-evaporation of condensate (the process by which acidic salts are deposited in concentration.

The condensate does have a high iron content, I have noticed and much of that is taken up by the marble chip tank. I have no data on how the pH is affected by this but am manually monitoring one installation.

The casting geometry (on the KN which is all I am describing here as a reference base), is compact, with diagonal channels for heat absorption but also for stress mitigation. I forget offhand the CI type they use; I do not think it was malleable but that would make some sense from a stress standpoint. The nipples are a graphite material but I have not examined one personally.

I mention the casting geometry because that is one feature which enables tolerating cool water return without cracking or deformation. The Taco plant uses two KN-20's to power their snow melt via an exchanger to give one cold-fluid application.

The turn-down on fire is a burner function of course, about 4:1 if not 5:1 depending on model, but it uses the Dungs gas valve, very helpful here in Boston where our gas pressures are limited to 4.0 inches guaranteed by contract (old gas light lines in use). The Dungs gas valve will operate at 2.0 inches and has been tested at less.

So, for what this is worth, as I suspect the Ray is the heir to this commercial line, these are some of the features.

(http://forums.invision.net/Index.cfm?CFApp=2&Message_ID=397038)

tim smith

Brad etc. Re: KN or Ray boiler

I understand the wash down of condensate and of course in the upper portion evaporation of same. My concern is down the road, the pin design will become clogged with corrosion, slash sluffing of cast iron. Looking at the design, this will be a bear to say the least to clean. Any thoughts regarding this concern. Tim

Lil-Roc

Looks cool... Danger Danger Will Robinson!!!!! It looks like something out of Lost In Space. I'd like to it in action.

Timco

I like the finished look as well...it was a task to get it in the basement, but it sure runs smooth!!!

Tim

Pete Caruso_2

NICE WORK! Please tell me....

Tim,

The .jpg shows neat, clean work. You obviously take pride in what you do.

I hope that you don't mind me bombarding you with questions. I'm new in my job and you are the first contractor I've had the chance to "meet" who has had his hands on rAy.

What do you think of the controls?

Did you enable SmartCycle?

How did that go?

Pete Caruso rAy National Sales Manager pcaruso@mestek.com

Timco

I don't think we set the smart cycle up. We just programmed a ODR curve and the basic WWSD features. This boiler was giving the customer a LO reading of all 'v's and another strange error message, but a new control with a later version of firmware solved that. The old controller also had an incorrect value set for the supply sensor and thought the supply water temp was always 17*. That was fixed with the new controller as well, and it modulated fine. I made a condensate neutralizer for it and it has been firing and running great ever since. (early feb.) Thanks for the compliments. The controls are great, and it was easy to pipe and wire. Luckily it was installed in a room with a window so venting and air needs were easy. As for the galvi and blk iron mix, I did what I had to so the cust had heat on a weekend...and would do it again...

Tim

Ted_5

What is the AFUE?

Is it tested to AFUE? Not any in house test numbers! Why does the KN10 and 20 only get just over 85% when tested by GAMA? Doesn't heat transfer better across thinner metels? So if the castiron gets thinner over time, then it will be at it's best just before it fails? What is the advantage to this desgn over stainless steel?

Ted

Unknown

radiantted

The info you seek is on the website,, just click downloads on bottom left of homepage,,, other claims are addressed there too.

Tom Hopkins

I'll give you one guess as to why this boiler is cast iron. Mestek manufactures cast iron. This is basically two end sections of a KN boiler bolted together. Slick looking beast and should last a long time. Just be glad it has a metal burner in it and not ceramic. POP!

Tom Hopkins

Oh yes. and the AFUE is heavily weighted toward the low input range so the higher the turndown, the higher the AFUE. This boiler is about 92-ish, I think.