Plugged Fire tube Hx

Tom_133

Hello all,

I was at my customers today to swap a venturi and igniter on a Prestige solo 110 I put in 9 years ago. This unit has been trouble free. I got a call about the floors being cold saturday and found a bad pump. As I was standing there I noticed it fired a little loud, so I looked at the venturi and it was super sooty but not broken, but I figured better get it done.

So today I went back and swapped the venturi, and igniter, I grabbed my test 320 to tune it up and the Co2 will not come up on high fire, on low fire its fine. Called TT, they say must be wrong venturi, its not. Then they said its gas pressure, its not. Then he had me test the outlet on the gas valve to see the negative it pulls when the fan comes on, its only pulling a -1.0 inwc.

He tells me fire side of the Hx is plugged. That answers my question as to why my numbers on high fire are whacky but then opens the door to a new one, why is it plugged and how to clean it?

Any thoughts? My thought was to use fernox ds40, pull off the top of the HX and hook up my transfer pump, put a bucket under condensate line minus the trap, and catch in the bucket what I pump into the top, do that for a half hour or so?

Alan (California Radiant) Forbes

Manometer on the outlet should only read -0.1", no?

Your cleaning method sounds good. You may also want bring your air compressor for those hard to reach areas.

I'd also replace the refractory while you're at it.

DZoro

Water also works by itself. Long pipe cleaners, or beer tube 3/16" cleaning brushes, depending on the dimple design.
D

Tom_133

Thanks guys,

So I went today did the job and my numbers came right up. Fernox is a good cleaner!

flat_twin

Just curious, how often was the HX opened up and cleaned? How much hard debris was building up in the condensate trap?
Thanks!

Tom_133

I have not touched that boiler in 9 years. The condensate trap was orange in color but no real scale to speak of. Also, I will need to go back and flush the onix tubing. Man I wish I didn't have any of that stuff out there.

Le John

I wonder what the record in years is for a mod con that has never been serviced is. Not that they should but how long can they go without service?

Tom_133

Le John

I am not sure how many years the record is, my guess was they were using someone else to service it, then they called and said "nope not using anyone else, just hasn't had any issues". It sort blew my mind!

Le John

I would consider 9 years of trouble free operation without 1 service call a very good track record for Triangle Tube.

bob eck

Is this boiler running on natural gas or LP gas?

Tom_133

LP

bob eck

9 years before having to clean a heat exchanger when heating with LP gas is a very long time.

djc2232

Im going to have my ECO 70 (LP) cleaned out this summer. Its only on its second winter and only does two heat zones. Had initial check after first winter run last summer and there wasnt much in the HX, some but not much. After seeing what one winter season does I wouldnt go more than two heating seasons without cracking into the HX and give it a good cleaning.

Weil Mclain says to only clean the inside with a vacuum cleaner and rinse out through the drain pan with water. Says not to use any solvent. Doesnt mention anything about a brush though.