Looking for esoteric Triangle Tube knowledge on the PG model

Teemok

Frist off, I've already been on the horn with 4 different TT techs and have been given mixed info from those consults.

I was asked to do an annual service on a Triangle Tube PG plus-35P (the last P is for propane) It's in a remote location, 1.5 hrs from me. The unit left the factory in 2004 (one of the last). I found it running with it's intake pressure switch tube disconnected. (safety disabled)
It shuts off and rapidly cycles the fan on and off if connected. I've determined someone swapped the switch for the wrong one and just left it rather than digging in.
Here's the thing: The switch's job is to verify that the combustion fan (munchkin style) is able to move the correct volume of air through the heat exchanger. A measure "A" to verify "B" arrangement. There are three different switches for these units and there's an intake air shutter that chokes the intake to limit air flow and create the correct negative pressure in the direct vent intake piping at the unit to keep the said switch closed. The shutter (adjustable disk style restrictor at piping connection) setting must match the switch and the burner size. So model size, gas type and altitude form a chart.
I was sent the manual by TT that is for the Delta PG models and the chart calls for a 3.35" w.c. switch. The subject unit is a PG "plus" model. This 3.35" contradicted what previous tech support advised. Confused I called again was told 2.7 is correct and I should call the senior tech who knows these things well. That's the guy who said 3.35" is correct but sent me maybe the wrong manual for my unit to prove it.
I found a different manual for the Delta "Performance" Plus and it's chart uses the "Plus" in the model number designation and calls for a 2.7"w.c. switch. Where did "performance" come from? I'm thinking this is the correct manual. I wish advertisement model names and actual model numbers were consistent.
My dilemma: The previous tech may have tried to replace the switch because the HX is restricted and that's what I'll find if I install the correct switch. Also the intake shutter may or may not be set correctly. Intake piping must be removed to check it.
Finally a question: Anyone have any experience with cleaning clogged HX or deteriorated turbulators on these units? What am I likely to find? I measured 2.6-2.7" w.c. at the intake switch sensing port. This is just at or under the switch's setting. I've not done combustion on it but it lights off ok. Maybe it has too aggressive of a flame. It's well extended off the burner and a bit uneven. I shut it down (vacation home) till I knew more. How would you proceed?

hot_rod

Some would suggest 20 years on a mod con is about the end of a repairable product
How many $$ trips and hours do you have tied up in this?

It commendable that you are trying to minimize there cost to salvage this unit.
Has it been serviced regularly? If not, cleaning that HX fireside may be opening another can of worms. Are you willing to warranty repairs to this old unit? Seems like any failure from here on is tied to you.

Teemok

Well @hot_rod , you nailed all that. I've only visited it once. Expansion tank, fill valve, leak, pumps, actuators check, etc. The problem is not mine personally. These are not true condensers and I don't believe it modulates. I get the point, it's service life is limited. I'm helping out a the company that employed the previous questionable tech. I already recommended It's time to replace. The customer is rightly un-confident and needs a clear story as to what's up. A delicate situation. As it stands, they want to toss more money at it to find out if it's still viable. It's hard for me to support that but I'm not the shot caller. If I had more info or experience with this model I'd have a firmer stance one way or the other. I was hoping someone could confirm that the Delta Performance Plus is the as labeled PG Plus model. That would clear up what the correct switch is. Weird that TT has two different switches and shutter settings for the 35P model. I can't see any difference between them at quick glance. Logic tells me I could close the intake shutter some and get more than 2.7" or even the 3.35" negative pressure. I would just effectively be reducing the firing rate. Re- tuning combustion mix of course. But..... I don't want to make a kludge that becomes a liability. Thanks for that word @Jamie Hall.

hot_rod

Tough call, it comes down to when to hold 'em, when to fold 'em.
I always try to do the best for the customers, affordable repairs. A portion of those come back to haunt you. Usually the jobs farthest from the shop

The best policy is to spell it all out on the service ticket I suppose.

EdTheHeaterMan

I had one customer that was really far away from the shop that installed his own Crown Freeport (older style) oil fired boiler. The oil dealer he used has 2 locations and the location that has its own service department and technicians was too far for them, but it was on the way for the fuel delivery driver that handled the location closer to me. I did the service for the other location’s customer. So this guy was out in Limbo!

I decided to look at it while traveling home from visiting Philadelphia because it was on the way. OMG this boiler was installed like a professional and when I opened it up after 2 years of operation, it looked like it was never used. Not a speck of soot, not a speck if white ash, really looked new. How this guy got it set up to burn that perfectly, I’ll never know.

I got this terrible feeling that if I made any adjustments the thing would soot-up in a week and I would have to go back for free and clean the thing. After only cleaning the dust off the fan blades and the air intake parts (not that much dust but enough to make a small pile on the floor), and changing the filter and changing the nozzle, The combustion numbers were perfect! Base of the chimney was spotless. I collected the $$$ and went home. This customer has purchased a maintenance agreement every year since, all the way up to selling my business.

That’s my ”too far away from the shop” story. I got lucky on that one. Best of luck to @Teemok on your adventure. I wish I had some more info on the TT Boiler. I only worked on 3 of them and do not remember that model

Teemok

"The best policy is to spell it all out on the service ticket I suppose."
This is the way! I've seen the value of writing it out so many times. But the way this company works, I send my report to the office and they copy what they will or won't and send it on to the customer. It's out of my hands.
Trouble is many customers don't read it, or if they do, they don't really understand it..... Safety, reputation, profit, customers best interests. Operating with "Best interests" in mind doesn't always make the customer happy. If it was easy, everyone would do it.