Is my Giannoni heat exchanger leaking?

BlueGreen

I went do the annual cleaning of my Peerless Pinnacle PI-140 that I installed in my house on Tax day 2002 and it now has what appears to be very small leak(s). In the pictures attached you can see the second and 3rd to last rib are rustier than the others and seems to have a sheen of water that has stayed on it even after I left the boiler open over night. There are also small droplets that form at a few high spots in the middle but don't appear to actually drip.

I am wondering if this is just leftover condensate that somehow pools at the top and slowly works it way down or is it actually leaking at at rate that is not much ore than sweating a little. I monitor the electrical usage of the system and can easily identify the spikes of the condensate pump running and it did not run over night so it is definitely a small leak if it is leaking.

Seventeen years is not to bad for a Giannoni so I am ok with replacing it if it is on its way to developing pinhole flowing leaks. I will be having a contractor do the install this time if needed as I don't have the time these days.

If there was a heat exchanger available, I would replace it instead of all new as everything else is working well.

Thanks.

Timco

Toast....

BlueGreen

Timco said:

Toast....

Thanks, Timco. Actually, I am leaning towards an HTP EP-110 for a replacement. Do you know of any Chicago area HTP dealers to recommend?

I will probably close it back up and limp along for DHW until it is replaced.

clammy

Just wondering was this in a hi temperature application .i ve never run into one where the heat exchanger looked so.peace and good luck clammy as a replacement how about a htp uft heard good things and 10to 1 turndown

Zman

I am wondering if inadequate flow combined with poor combustion is responsible for the damage? It sure looks like it has seen excessive heat.

hot_rod

Was it piped with a dedicated circulator

It does look like it has been over-heated, lack of flow or scaled insides are the common causes. If so a testament to the abuse that HX can take when not flowed properly.

A fire tube design doesn't "fix" crappy fluid conditions, keep an eye on what you fill with and yearly fluid test with HX cleaning.

What type of tube is it connected to?

That type of HX properly piped and maintained certainly can last 20 years we are finding.

BlueGreen

The pictures are without a complete cleaning. I just vacuumed out the reasonable amount of coffee grounds and brushed a little with a nylon brush and vacuumed again. Normally I would use CLR and brush real well and give it the credit card treatment and it would look pretty good, but given it was leaking I haven't done that.

I didn't want to go into all of the details in the initial post, but yes it is piped to an indirect (170 boiler max, 135ish DHW temp mixed down to 120), has a buffer tank piped on it's own circulator, is on ODR with max temp of 160 from a Tekmar 422 (I made a control to cap the 422's aggressive modulation signal based on ODR to lengthen runtimes to near theoretical maximums), so if anything, this boiler is the victim of too much condensing which seems to be the consensus from what I have read on HX longevity.

I did notice the rustiness of the second and third tubes from the back the last few times I cleaned it. I never put any water treatment in the system, but that will be part of the new install.

Nothing wrong with Lochinvar or other vendors, but I am not sure if the firetube HXs have been in the field long enough to prove their longevity and I don't know if they are really any easier to clean. I can clean a Giannoni and they can last if treated well as you say. There is probably something better than CLR for cleaning the deposits. I have had techs out to clean the boiler in the past it was usually a disaster, like not flushing out the condensate trap and not tightening the burner screws enough so condensate was leaking out. I would like to have a tech out for combustion analysis. When I did in the past it was always in spec there was nothing to adjust.

New boiler requirements:

0-10v boiler modulation input
10-1 turndown
0-10v pump modulation output for Armstrong Compass H
90-110 mbtuh input
Floor mounted, but some re-piping on the opposite wall would allow wall mount.

From my research, that narrows it down to HTP EP line or Lochinvar. As always, it is really the contractor and distributor support that matters in the end.

I am in near west chicagoland. Steam Whisper/Boiler pros and Suburban Boiler are listed on find a contractor. Not sure if Boiler pros does modcons. Anyone else to recommend?

Thanks.

hot_rod

It's alway interesting to cut open an old HX like that and see what's up. It only takes a small amount of scale buildup inside to start stressing the coils.

I see"Wheels" at NTI promoting a large round plastic brush in the NTI kit, looks like a carwash brush for cleaning those type of HX. Maybe it goes on a cordless drill, anybody use one yet?

I think the boiler selection will be limited by the 0-10 output for the circulator that you desire?

The wholesalers and reps can usually steer you to the knowledgable contractors in an area. Try Darekn@lyall-thresher.com for some choices in your area, he is out in the field a lot and sees the good and bad.

Henry

Warping the HX like that is a sign of low flow. Delta T should be 20 to 25F ideally. Some manufacturer I & O manuals will even show up 40F DT. I had a long conversation last week with the head of engineering of one manufacturer about this. Plumbers will try to use the smallest pump and have a DT of 35 to 40F because of the cost of a proper pump. BTW a "Dirtmag" before your pump will save your new boiler.

BlueGreen

Thanks for all of the replies today. The hx sat open all day and there is no more dripping but the streaking on the back tube continues. It's not leaking enough to make the condensate pump go so I sealed it up so we could have a hot water while I get some estimates.

I have a dirtmag seperator but never got around to the repipe where that was going to be installed.

The warping in the HX is hard to see but maybe it is there. It probably bounced off the high limit a few times but other wise maybe. I have some calls into contractors and HTP for an installer.

Thanks again all.

Zman

The fire tube has been around since the early triangle tubes ~15 years. They are a solid product. They are natural sediment traps so be sure to put in that dirt mag.
The new Lochinvar WHB is sweet!

BlueGreen

Thanks for all of the replies. The hx sat open all day yesterday and there is no more dripping but the streaking on the back tube continues. It's not leaking enough to make the condensate pump go so I sealed it up so we could have a hot water while I get some estimates.

I have a dirtmag seperator but never got around to the repipe where that was going to be installed.

The warping in the HX is hard to see but maybe it is there. It probably bounced off the high limit a few times but other wise maybe. I have some calls into contractors and HTP for an installer.

Thanks again all.

Timco

BlueGreen said:

Timco said:

Toast....

Thanks, Timco. Actually, I am leaning towards an HTP EP-110 for a replacement. Do you know of any Chicago area HTP dealers to recommend?

I will probably close it back up and limp along for DHW until it is replaced.

I show these results for a local Rep. They could certainly recommend a wholesaler in your area and a company that installs our products. Best of luck! Sorry for the delay in response, I check in once a day and it has been very busy lately. Please reach out to me directly if you have any questions.
tim.white@htproducts.com

KAST Marketing
1925 Holmes Rd. Unit 200
Elgin, IL. 60123
sales@kastmarketing.com
Office: 630-227-0600