IBC Aluminum/Copper Modcon HX

SuperJ

I'm considering a IBC HC or DC boiler for my house (similar boilers, one is the combi model).

They both use a cast aluminum heat exchanger with copper water coils in embedded. So flue gases touch the aluminium and water only touches copper. The combi model has dedicated copper passage ways in the HX so there are no solenoids or water to water HX.

I'm not too concerned about the copper and water, but was wondering about the life expectancy of aluminum heat exchangers when exposed to the acidic condensate?

IBC has a pretty decent warranty. And people seem to speak highly of them.

Realistically I would love to step up to the IBC SL firetube or Lochinvar firetube, but it means spending significantly more money.

The only reason I'm considering the HC/DC boiler with it's aluminum is that I can't seem to find any negative reviews or horror stories. There are some general discussions and schools of thought that aluminum has no place in a boiler HX though, but that is generalizing. Has IBC done something to their aluminum to make it robust?

Realistically, I would hope to get a 15-20 year life out of a properly maintained boiler regardless of the HX technology.

NY_Rob

Did you consider the value priced HTP fire tube boilers with SS HX?

SuperJ

NY_Rob said:

Did you consider the value priced HTP fire tube boilers with SS HX?

They come here a lot in discussion, I'll have a look. I work for a major commercial mechanical company (in their controls dept.) and was mostly looking at IBC due to being able to get a good deal through our wholesaler arrangements. We don't have any suppliers who offer HTP directly.
I'm a little baffled that HTP doesn't have any sales representation in Southern Ontario, it's a huge percentage of the total Canadian population.
http://www.htproducts.com/find-sales-representative.html

But, the more I think about it the more I think about the more I think I'll hold out for a SS HX no matter what the brand.

NY_Rob

I'm going into my 3rd winter with my HTP UFT-80W... ask as many questions as you'd like. I have a pretty decent handle on my setup at this point.....

HTP is a little odd, it seems they don't push their mod-cons at all. Even here where they have authorized sellers (Blackman Plumbing Supply) they don't stock the HTP mod-cons or any parts for them. I had to special order my boiler. The good part is since Blackman is a factory authorized HTP seller I got warranty parts through them quickly and at no cost.

hot_rod

They seem to have a great reputation and they pioneered that boiler brand in Canada before we had many in the US. I think the company sold or merged and we see more distribution down in the US now.

kcopp

I install the IBC HC/ DC boiler more then any other boiler.
Very simple design.
Only 5 moving parts.
over 1.5 million in the field...... Not a single HX failure.
Most of the issues w/ aluminum are probably system water related. (although most HX issues are system water issues)
SL is a nice unit. Control is a wonderful thing.
However I would still install the HC in my house w/ a properly sized indirect water heater.

Gordy

What size boiler do you need?

Is low end modulation important. The uft 80 gets down to 8k and is 10:1 tdr.

While the IBCs lowest is over 13k with a lower tdr.

I have nothing negative about the IBC. Except that.

It’s possible the price point of the uft may be lower than an IBC even with your discount. Pure speculation though.

One other would be parts in your area. I’ll leave service out of it since you are capable.

I won’t compare hxs since the aluminum is not in the water side.

SuperJ

It kinda depends on whether I go combi or not. My heat loss is about 40kbtu for my house, and I'm microzoned with panel rads and TRVs. I was going to put a small buffer tank in no matter which route I go.

So the consensus is the aluminum on the flue gas side is not a problem in a modcon? Or at least for the IBC HC/DC?
If I go with the SL they have a 10-85kbtu.
My coworker has a the VFC15-150 and it runs like a dream for him.

I'd love a 45kbtu boiler with a 10:1 turndown but no one makes one.

Gordy

if you are 40 k load at design, and micro zoned you would get more benefit from the UFT 80 with a 10:1. Even with 8k lowend you would need buffering.

hot_rod

It seems you either love or hate aluminum block boilers. It's rare to find a middle of the road opinion.

If you talk with the early adopters that used glycoled aluminum, like most of Colorado Pallet loads of failed aluminum HX went back for warranty from all the suppliers. They didn't bother sending one at a time, seeing so many fail they just banded a pile at a time to pallets.

Changes have been made to the alloy, Al friendly glycols are available, and religious testing of the glycol ph a known requirement.

One factory guy told me they have tried 1/2 dozen different coatings and treatments to the aluminum to deal with fluid on the inside and 4 Ph condensate on the outside.

Thermal conductivity of aluminum is 118, copper 223. so adding the copper helps that transfer quite a bit.

NY_Rob

Can you combine any of your micro zones into just a couple of larger zones to make the 8K BTU minimum fire rate of the UFT?

SuperJ

Do you know if the UFT has any ramping functions to limit the fire rate initially (like Lochinvar)? I'd like it to hold at min fire for a while after start even if it is way off set point.

I think if I pipe it primary secondary, and use aggressive ODR and cycling control with wide deadband, I should be able to run it. My TRVs are setup more as high limits, with the primary temp control being the ODR, this means that I usually have flow everywhere (most of my panel rads are at least warm on top most of the time). If I overheat the water then the TRVs clamp down and flow gets reduced.

@Harvey Ramer has installed similar setups. This is what I'm going for (except I have lower mass panel rads instead of high mass cast iron). https://www.phcppros.com/articles/7804-when-old-tech-meets-new-tech

NY_Rob

SuperJ said:

Do you know if the UFT has any ramping functions to limit the fire rate initially (like Lochinvar)? I'd like it to hold at min fire for a while after start even if it is way off set point.

Yes, it has "step modulation" function for both spaceheating and DHW...

NY_Rob

... it also has a "Heating Capacity" function where you can limit the max output by up to 50% of max.
So if you have a small 35K BTU heatloss, set combustion limit to 50% (40K BTU's) and it will take longer to get up to setpoint too.

You can use "Step Modulation" and "Heating Capacity" together to get longer burn times and slower ramp up's to setpoint.




For a "low end" , budget minded boiler it has a ton of features... take a look at the install manual, etc...

http://www.htproducts.com/uft-documents.html

ice4me

I would be interested to know if you find a distributor for HTP in Southern Ontario. I'm in a similar situation to you - I really like the Lochinvar Knight series, but its hard to ignore the cost savings of HTP's UFT line.

SuperJ

I emailed HTP to inquire about Ontario distributors. We'll see what they come back with. Oddly it seems that my area codes (519,905) are specifically excluded from their distributor lists.
I wonder if some company has some sort of unpublished exclusive on the region?

NY_Rob

The UFT with an Alpha is a great combination....

Last night I was working in my basement, less then 8ft away from the boiler and I heard one of the zone's overhead supply pipe creak a few times. I thought that was strange since the boiler was off.
I went over and looked at the boiler... it wasn't off... it was firing at it's lowest rate and the Alpha was silently pushing water at 2gpm for the one open zone. The two of them are really quiet together, especially when the UFT is just putting along on low fire.

ice4me

Any word back from HTP?

SuperJ

They never responded. I filled out a form on the website and emailed them separately.

Harold

Just my two cents on Al in a boiler. Boiler core all Al. Small boiler 50 KBTU. First core eaten through. This one probably had water issues. Two subsequent boiler cores developed holes. With good water. Roughly 4 years/core.

Inside, the one core I took apart had what I (a causal and unskilled observer) believed the combustion chamber of the core had a hole eaten from the inside. I have not dissembled the next two.

I briefly thought about going for a fourth core, because my stack of cores looks lopsided with only three. But I got over it.

I will never again install a boiler with Al in contact with anything. Be it water or multi-material electrolysis currents.

SS would appear to be the solution, if you will excuse the term.

kcopp

What manufacturer? boiler make/ model?

Gordy

The IBC HX is a different animal.

Eastman

Are there any copper water tube modcons?

kcopp

Eastman said:

Are there any copper water tube modcons?

I don't think so… Embassy Axia was near condensing. The IBC DC/HC has copper water tubes but they are embedded in the Aluminum block.

Eastman

I wonder why that is the case. But I can't think of a reason off of the top of my head.

Gordy

Both metals have higher heat transfer than SS. The copper is better at handling the water side water quality issues. The aluminum is lighter, and cheaper than copper to handle the fire side.