HTP UFT Problem

Ironman

I was on a job yesterday finishing some items when I discovered the UFT 100 that we installed in November was flashing a code for ignition failure and had locked out. I checked all the things that the manual called for plus some more that I knew might cause it - all to no avail.

I decided that something must have gotten sucked into the burner so I took it apart and this is what I found lodged in the throat just before the burner:



It's part 46-1 the "air damper". It had broken at the tabs that hinge it. Has anyone else experienced this? We've put several of these boilers in and I'm wondering if this is gonna be an issue with all of them.

Naturally, I didn't have the part so I fired the boiler up without it and it ignited fine each time and ran well.

Does anyone know it's purpose? Is it to prevent ignition blow back? Part 46-2 is a plastic web that holds it partially open.

I called HTP tech support this morning and left a message for a return call after being on hold for about 20 minutes. It 10:00 PM and I still haven't received one. Real good tech support there HTP - NOT!

Timco

I know for a fact they are short handed in tech support. I’m not familiar with that model. Been working with EFTC and liking them so far.

Harvey Ramer

Thanks for sharing your find.

NY_Rob

@Ironman Sorry you're having issues....

Last fall when I was brainstorming w/HTP tech support (Brendon) over which spares I should keep on hand for my HTP UFT-80W the "air damper" was one of the parts he suggested I stock. He told me he has seen them go occasionally.
If you're going to order one (7855P-368) .. good to order a spare and keep it on site.

I also ordered 46-1 the "Air Damper Guide", 46-3 "Fan Outlet Gasket" and 47 "Burner Inlet Channel Gasket" so I have the full set of gaskets, etc... onhand to complete the job.

If you install the HTP UFT boilers, here are some common parts you may wish to keep locally for emergency repairs for the UFT80 thru UFT140 models..

7855P-262 $15 Air Pressure Switch
7855P-007 $58 Ignition Transformer
7855P-092 $29 Exhaust Temperature Sensor
7855P-068 $23 Ignition Rod
7855P-252 $6 GASKET, IGNITER
7855P-030 $18 CH Supply Temperature Sensor
7855P-029 $9 Water Level Detection Sensor
7855P-031 $5 Flame Sensor (2)
7855P-097 $9 CH Return Sensor
7855P-066 $7 Burner Overheat Sensor (2)
7855P-025 $200 Blower Motor (inducer fan)
7855P-344 $91 Display Panel
7855P-308 $219 Control Board (no gas sensor on board)(firmware rev 0012)
7855P-381 $149 GAS VALVE ASSY
7855P-249 $2 O-RING, BURNER PLATE (2)
7850P-210 $6 EXHAUST & INTAKE GASKET
7855P-368 $8 Air Damper
7855P-369 $7 Air Damper Guide
7855P-425 $11 Fan Outlet Gasket
7855P-370 $8 Burner Inlet Channel Gasket
(FYI-the $$ may be off by $1-$2 per part because the list was compiled 1.5yrs ago... there have been some slight increases since then.)

Ironman

Thanks Rob.

I'm gonna give the list to my distributor. I'm old school: I believe it's the distributor's job to stock proprietary parts, not the contractor's.

NY_Rob

Ironman said:

Thanks Rob.

I'm gonna give the list to my distributor. I'm old school: I believe it's the distributor's job to stock proprietary parts, not the contractor's.

+1
If they sell you the boiler... they need to stock the common parts!

HomerJSmith

It is to prevent burner gasses moving into the blower, I believe.
Thanks for the tip.

Dennis

Sure hoping the combi boilers don't have that part. So far so good, only one with an issue of a bad main circuit board. The boiler came out of the box smelling like it had an electrical problem like overheated electronics.

hot_rod

I thought it had something to do with the turndown rate?

lchmb

Ive called a few times in the last month while working on an issue. great people who do help at HTP. with that said, I have left my number twice on the system. never recieved a call back..i'd call and wait..

DZoro

At least you are able to get to it.
Navien has one that is 98% improbable to get to. Yes you can get to it but your not going to like it. Phillips screws partially covered up from main H/E installed at factory no room for a screw driver that is not a 90* angle. Don't dare strip out the Philips. Takes hours for what should be a simple fix.
I found this out after very strong winds forced the damper to a stuck closed position. Wasn't impressed, btw why plastic?
Even in the intake part of a boiler things get hot and deteriorate. The TT didn't have them, but eventually the plastic blower wheels just deteriorated instead.
Sorry done with my rant.
Onward
D

Tim McElwain

I believe the door is to prevent gases created by overheating PVC and CPVC being recirculated which are chlorine gases which cause deterioration of the metal insides of Mod/Con boilers.

Another reason to use Poly-Pro.

Ironman

lchmb said:

Ive called a few times in the last month while working on an issue. great people who do help at HTP. with that said, I have left my number twice on the system. never recieved a call back..i'd call and wait..

The thing that gets me about this is that leaving your number with the automated system is supposed hold your place in line. I can't believe that there were so many in line they couldn't get back to me by the end of the day. I left the message at 8:50am.

Yesterday, I connected the wiring to the indirect, but the boiler wouldn't recognize the call from it. It went through the parameters several times and it is programmed correctly.

The owners are moving in this coming week and I need a properly functioning boiler! ( It is space heating fine).

lchmb

Sorry I went through the same thing.. I'm still waiting on a call from last week...I just called mid morning and waited 10 minutes..I know they had some issues last week with power and phone loss... If not maybe try Emerson Swan. I can set you up with a number in NH if that helps

Ironman

Dennis said:

Sure hoping the combi boilers don't have that part. So far so good, only one with an issue of a bad main circuit board. The boiler came out of the box smelling like it had an electrical problem like overheated electronics.

They do have it. The combi is the same boiler with a domestic heat exchanger added.

hot_rod

Is it gas or LP?

When I installed my Nobel I had to add the air shutter and change the venturi to convert it from NG.
There are actually two movable shutters in this style. I think it has to do with operation at low turndown rates. Rumor I heard is it is what is used to get 5-1 turndown boilers to 8-1 or higher?

lchmb

btw..I was told by another manufacturer the door's are there to stop air from flowing through the system after shut down to keep the block from freezing in an off cycle.. not sure how accurate it was but i do know on the commercial unit's they do not want it operating without it..

Harvey Ramer

I would suspect the flapper may be necessary at low fire to prevent flue gas reversion. Lets say the appliance was power-vented. At low fire, the fan may not be able to overcome wind pressure from the outside of the building. This could cause the flue gasses to come spilling into the room through the intake, plus damage the venturi assembly. The flapper may act as a check valve to prevent this.

I'm not saying that's the reason for it, but it makes sense to me.

Harvey Ramer

Bob,
I have called them before and left my number on multiple occasions. If they don't call back within a few hours, I call again and usually get through. It seems that active calls may take priority over saved calls?
Anyway, my apologies for chipping the line. But I will likely continue

NY_Rob

I'm actually surprised/happy the boiler ran without the flap in place. Not many parts can be removed from a mod-con and it can still run.

In this case- the manufacturer (HTP) needs to be more proactive with it's distributors and require they keep at least a bare minimum of common failing replacement parts on hand locally (for the boilers they sell) so the installer/service man/homeowner isn't hung out to dry waiting for a $10 part (+ $40 overnight shipping) to arrive from Massachusetts.

Ironman

hot rod said:

Is it gas or LP?

When I installed my Nobel I had to add the air shutter and change the venturi to convert it from NG.
There are actually two movable shutters in this style. I think it has to do with operation at low turndown rates. Rumor I heard is it is what is used to get 5-1 turndown boilers to 8-1 or higher?

It natural.

The part in your pic is on the intake side of the blower. They call it the "air gas mixer". The air damper that broke on mine is on the discharge side of the blower. The "air damper guide" actually holds it partially open.

The burner ignited fine without it and ran fine from low modulation to high. I did not have time to confirm combustion with an analyzer that afternoon. I will when I go there tomorrow.

The thing that concerns me about all this is that this part failed after only three months of operation and the way it's constructed looks very cheesy with the two small tabs acting as hinges.

kcopp

I find it odd that its made out of plastic.
The IBC unit I install has a flapper on its discharge but its made out of a silicone rubber. The Bosch Greenstar also has a device like this and its also rubber. Short term its fine that is not on there but it protects the fan/ motor from cold air and rain.

Ironman

Keven, it's rubber, not plastic. IDK who said it was, but not me.

Ironman

UPDATE
I just talked to Brendon at tech support and he said the air damper really isn't necessary on the smaller units and could be left off.

He did say that it was ABSOLUTELY necessary to have it on the larger 175k and 199k btu units.

Let me caution: this is in the context of the UFT boiler only.

NY_Rob

^ That's great news Bob, thanks for sharing.

Glad you spoke w/Brendon... he's been there a while and is pretty knowledgeable. I usually try to connect w/him when I have a question/problem.

So are you going to leave it out permanently?

Will be interesting to see the CO/CO2 numbers at low and high fire to see if they change without the flap.

I never had the fan off my UFT.. is the fan rotor metal or plastic?

Mark Eatherton

Could this damper be for those parallel boilers with a common vent?? Back draft control?

ME

Ironman

2nd UPDATE

I talked with Dave at tech support and he sent me this TSB about the flapper. He also said it could be left off of the smaller models, but the bulletin says it's necessary.



The boiler in question is igniting, modulating and firing properly from low fire to high without the flapper.

Ironman

NY_Rob said:

^ That's great news Bob, thanks for sharing.

Glad you spoke w/Brendon... he's been there a while and is pretty knowledgeable. I usually try to connect w/him when I have a question/problem.

So are you going to leave it out permanently?

Will be interesting to see the CO/CO2 numbers at low and high fire to see if they change without the flap.

I never had the fan off my UFT.. is the fan rotor metal or plastic?

I'm gonna leave it out unless I see an issue.

The fan is plastic.

NY_Rob

^ Thank you!


Out of curiosity... how many hrs labor to replace the failed part (if you had the part on-hand) ?

Wonder if it's worth replacing the original OEM flapper before it fails with the new/improved flapper?

Tim_9

Appreciate the update, mine has the white mark on the flame rectification shield but not on the exhaust terminal so I assume it's the revised version?. I purchased the unit in November but didn't get it till later in the winter. Thanks again...

Ironman

NY_Rob said:

^ Thank you!


Out of curiosity... how many hrs labor to replace the failed part (if you had the part on-hand) ?

Wonder if it's worth replacing the original OEM flapper before it fails with the new/improved flapper?

If you're talking about actual time it takes from opening to closing the boiler, less than 1/2 hour.

If it works without it and the combustion numbers are good, I'd leave it out.

kcopp

It will be interesting to see what the long term ramifications are...

If they put it in there.... then it has a purpose.

NY_Rob

Thanks Bob,
Fortunate it's not a big deal to service it, but right now if you have one and it fails... you don't have much of a choice- it's backordered from HTP anyway

I've been kind of chasing combustion numbers on my UFT-80W since I had an ignition failure back in Jan (due to running lean).
I set the low fire CO/CO2 numbers via the throttle adjustment at low fire per the I&O manual... button up the cabinet... check it a week later it's either higher or lower then when I set it last. Readjust to factory spec, check in another week and it's higher or lower again.
(Factory spec is 8-9.5% CO2 on low fire).

1/23/18 Error code 10 (flame has extinguished 5 times)
Turned throttle 1/8 turn clockwise (richer) boiler fired/ran
Read CO2 at 7.7% after boiler running again
1/23/18 Set CO2 to 8.9% (on low fire)
2/10/18 Read CO2 at 10.1% (on low fire)
2/10/18 Set CO2 to 8.9%
2/18/18 Read CO2 at 7.8%
2/18/18 set CO2 to 8.9%
2/25/18 Read CO2 at 9.8%
2/25/18 Set CO2 to 9.3%
3/10/18 Read CO2 at 9.5%
3/10/18 Set CO2 to 9.1%
3/31/18 Next reading

Now I'm wondering if I am having some sort of issue with the flapper on my (1.5yo) boiler?
I originally thought it was maybe the gas valve going south, Brendon at HTP told me the gas valves have been solid and rarely give problems.

NY_Rob

My last order of spare parts from HTP arrived yesterday...
The one week+ hold was due to the flapper being backordered.

FWIW- the new flapper has the "F" molded in to rubber, so it's from the new batch. The "hinge" area seems especially flimsy/very thin... seems like you could snap it off the main body by just removing it from the plastic bag if you didn't coax it out.

I hope it's not going to become a chronic problem on the UFT line.

HomerJSmith

A combustion analysis is a snapshot in time. The combustion curve changes over the operation of the boiler, which is why you run an analysis when the boiler is at the greatest percentage of operating parameters. Usually, when the boiler has been running for a time and is at its peak performance and the changes you make to combustion will occur most of the time during boiler operation.

NY_Rob

The UFT series has a DIP switches on the controller board.
Two of them are used for CA... one sets it on low fire (this is where you perform the CA and make gas valve adjustments), the other sets it on high fire and is only used for CA observations- no adjustments can be made on high fire.

In my mind, if you set it on low fire via the DIP switch... let it stabilize/run for 10-15min and perform the CA- you should get repeatable results one week after setting it.

GroundUp

@Ironman I was wondering if you ever replaced the flapper? I seem to have missed this thread before starting my own, but a Google search led me back here. If tech support says it's okay to leave it out, I may go that route with my troubled unit if it happens to be damaged when I return

Ironman

Well, unofficially, they said it was okay if it was one of the smaller sizes on natural gas and not common vented with another one. Officially, the TSB says it has to be there.

GroundUp

So..... Did you replace it?

Ironman

No.
Actually, I don't remember right now.

scaloo134

After literally months of troubleshooting and two supposed expert hvac techs stumped, I fished the broken air damper out the burner inlet channel tonight. I made an account just to say a big thanks to everyone on this forum!