Noisy Hydro Flame (Atwood) Furnace

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Noisy Hydro Flame (Atwood) Furnace

November 21, 2016, 11:33:58 am

Stern small furnace, shows a rebuild in 01. First thing in the a.m., it will fire up the fan, click & heat, a minute or so later, a noise like a fan blade hitting something comes on. Shut-down, fire it again and it works fine. This has happened three times in the past few months.
Any clues? Looks like fun to pull! Thanks, M

Re: Noisy Hydro Flame (Atwood) Furnace

Reply #1 – November 21, 2016, 11:41:53 am

Mike, I had same problem a couple years ago and while at Q Ken Hat took it apart in 10 mins and fixed it. He also oiled the brgs and moved the fan slightly back away from end cowling as it had moved a touch and that caused the noise. Nice and quiet since then. SO, secret is to go to Q and see if they turn up. He has taken a few apart I think and knew exactly which screws/ wire connections to remove. I can say it all took him around 30 mins or so to have it out and back in. I seem to remember there is also a topic on doing just that somewhere on this forum and a diagram of thing s to take off.
JohnH

Re: Noisy Hydro Flame (Atwood) Furnace

Reply #2 – November 21, 2016, 11:48:57 am

Mike, found this in search. Gary B has done it too.

Atwood Hydroflame Furnace UPDATE
Yes, You have to remove motor. Not simple, here are major steps.
Open Outer door
Remove plastic cover
Loosen wingnut to left of exhaust tube.
Pull exhaust tube out, it is just pushed into plenum, probably rusty but keep trying, just wiggle straight out..
Remove screws holding motor shroud, you will need a long nut driver to reach one in back..
Partially remove motor, then use a long shank Allen wrench to loosen blower cage from motor shaft.
Remove motor.
Also , as you go you will have to disconnect the various wiring connectors, label them so you know how to replace them.

John H

Re: Noisy Hydro Flame (Atwood) Furnace

Reply #3 – November 21, 2016, 11:55:51 am

Not too bad once you start ripping into it. I've had both of ours apart and got them back together without any left-over parts!

Re: Noisy Hydro Flame (Atwood) Furnace

Reply #4 – November 21, 2016, 12:08:13 pm

Quote from: John Haygarth – November 21, 2016, 11:41:53 am

Mike, I had same problem a couple years ago and while at Q Ken Hat took it apart in 10 mins and fixed it.

Thanks, Guys. We know Ken and Dori. Only problem, he's SO DAMN EXPENSIVE! I'll prolly have to buy him a bottle of Jack Black and pay for their site if he comes down here!

Re: Noisy Hydro Flame (Atwood) Furnace

Reply #5 – November 21, 2016, 12:19:08 pm

Meet him at Q- no site charges there!!
JohnH

Re: Noisy Hydro Flame (Atwood) Furnace

Reply #6 – November 21, 2016, 12:21:06 pm

Quote from: mike leary – November 21, 2016, 12:08:13 pm

Thanks, Guys. We know Ken and Dori. Only problem, he's SO DAMN EXPENSIVE! I'll prolly have to buy him a bottle of Jack Black and pay for their site if he comes down here!

@Mike,

Come to Q and we'll work something out.

If not we may be coming thru Aho on our way to Tucson.

If you can't wait here is a good video that takes you through it.

http://www.youtube.com/watch?v=d7YTOcSPOyI

see ya
ken

Re: Noisy Hydro Flame (Atwood) Furnace

Reply #7 – November 21, 2016, 12:32:54 pm

Quote from: kenhat – November 21, 2016, 12:21:06 pm

Come to Q and we'll work something out. If not we may be coming thru Aho on our way to Tucson.

Thanks, Ken, would rather not attempt it without adult supervision, then I can help others down the road. Be great to see you guys down here. By just turning the furnace off when it gets noisy and firing it up again, am I in danger of trashing the whole thing?
That was Jack Black, right?

Re: Noisy Hydro Flame (Atwood) Furnace

Reply #8 – November 21, 2016, 06:08:07 pm

Change the motor. The bearings are shot. And probably the brushes worn too. I found it several places online for around $60-80. Video above shows how to do it.

Mine does exactly the same thing. When it's cold, it's stiff to spin the fan. In fact, last night it blew the breaker! I'm replacing my motor soon, once I get home and some downtime.

Re: Noisy Hydro Flame (Atwood) Furnace

Reply #9 – November 22, 2016, 10:40:18 am

@Mike,

You might get by with just lubing the bearings. You don't have to pull the motor just the cover and maybe remove the fans. I use TriFlow. It's thin enough that it will flow into the bearing and comes with a flexible tube to snake around obstructions to get to the bearings.

Tri-FlowTri-Flow Superior Lubricant - 2 oz. Drip Bottle

Edit:
"That was Jack Black, right?" Jim Beam when I'm buying Makers Mark when somebody else is.

see ya
ken

Re: Noisy Hydro Flame (Atwood) Furnace

Reply #10 – November 22, 2016, 11:23:23 am

Go figure. This morning, it fired right up, no croaking! $:-\$

Re: Noisy Hydro Flame (Atwood) Furnace

Reply #11 – November 22, 2016, 12:37:19 pm

Mike, it will make noise again when unused for a while. Though some here claim to have lubed the bearings, it's really hard to get anywhere near the bearings, and the design of the motor really doesn't let oil get into the bearings.

Also, the brushes and commutator wear out as well. Face it, the unit is old and has a finite design life--the repair to do it correctly is not that expensive. This place is one that has the better prices I've seen. I don't know what BTU/hr or model furnace you have, but they have all of them in OEM and aftermarket. Just touch it once and fix it right: (35 and 40,000 btu/hr Atwood Furnace Blower Motor 37357 | pdxrvwholesale )

Re: Noisy Hydro Flame (Atwood) Furnace

Reply #12 – November 22, 2016, 06:46:51 pm

I replaced the motor in mine a few years ago when I was having some issues with it. It is well worth the money but after replacing the entire furnace with an Atwood 2 stage furnace, I would never consider going back. It is near silent when operating on low speed (which is nearly all the time unless the temperature drops more than 3 degrees below the set point).

Re: Noisy Hydro Flame (Atwood) Furnace

Reply #13 – November 22, 2016, 06:58:28 pm

Quote from: rsihnhold – November 22, 2016, 06:46:51 pm

It is well worth the money but after replacing the entire furnace with an Atwood 2 stage furnace, I would never consider going back. It is near silent when operating on low speed (which is nearly all the time unless the temperature drops more than 3 degrees below the set point).

See my other thread about buddy heater and furnace. I'm actually in the process of converting mine to a 2stage unit.

Re: Noisy Hydro Flame (Atwood) Furnace

Reply #14 – November 22, 2016, 07:33:38 pm

Chick, No parts left over? That's where I get the stuff to fix the next project. Don't know what i'd do if all the parts went back in.

Re: Noisy Hydro Flame (Atwood) Furnace

Reply #15 – November 22, 2016, 10:13:55 pm

Robert,
Which one did you go with? I notice that the 25,000/40,000 BTU model has a max current draw of 15 amps on high but the one that is 23,000/34,00 BTU unit is a little of over 11 amps on high. Would like the highest capacity possible with only one furnace, but we want the quietest possible unit that will do the job. The current single furnace is 35,000 BTU but sounds like a volcano erupting...
Don

Quote from: rsihnhold – November 22, 2016, 06:46:51 pm

I replaced the motor in mine a few years ago when I was having some issues with it. It is well worth the money but after replacing the entire furnace with an Atwood 2 stage furnace, I would never consider going back. It is near silent when operating on low speed (which is nearly all the time unless the temperature drops more than 3 degrees below the set point).

Re: Noisy Hydro Flame (Atwood) Furnace

Reply #16 – November 22, 2016, 10:22:51 pm

Is the two stage conversion a complete new heater ?
Is it a straightforward swap and whom has the best price.
Jim

Re: Noisy Hydro Flame (Atwood) Furnace

Reply #17 – November 23, 2016, 12:04:32 am

Kind of highjacking the thread but I guess we are still on topic with "Noisy Hydro Flame". Don't think Mike will mind...

I upgraded both my furnaces to the 2-stage Atwood. The 25,000/40,000 BTU units. If I had it to do over again I'd go with the 23,000/34,00 BTU units. The 25/40 unit is much quieter then 40,000 BTU unit it replaced but would still like it to be quieter. With 2 furnaces I think I'd have plenty of BTUs. So far the only times the 2-stage has gone into high speed mode is when I purposely put it into high-speed and I've only done that to test it.

The one drawback to the 2-speed furnaces is the thermostat. You have to use Atwoods thermostat. It uses a non-standard variable voltage to switch between low & high speed. I had to send back both of my thermostats for replacement after they malfunctioned. (would start the fan but never light the burner or jump from low speed to high speed then back again) Atwood replaced them but took several weeks to ship them. The new thermostats have worked perfectly so may have just been a problem with the batch I bought. The other issue is that the thermostat costs about $180 apiece. So once out of warranty theres that.

see ya
ken

Re: Noisy Hydro Flame (Atwood) Furnace

Reply #18 – November 23, 2016, 12:09:24 am

Quote from: Jimmyjnr – November 22, 2016, 10:22:51 pm

Is the two stage conversion a complete new heater ?
Is it a straightforward swap and whom has the best price.
Jim

Yes it's a complete new unit. It is a straight forward swap. The only real trouble I had was wrangling the copper tubing out of the way while removing/installing. I think I paid around $650 each for my furnaces. The best price I could find at the time.

see ya
ken

Re: Noisy Hydro Flame (Atwood) Furnace

Reply #19 – November 23, 2016, 12:22:19 am

Thought I'd mention the only reason I replaced instead of repaired my furnaces was the the burner flue rusted out on both of my units. On my furnace the the burner flues are no longer available. At least I couldn't find one. I tried using one of the newer style burners (they look very similar and fit perfectly ) but they would run for a while then start making a farting noise ( luckily no smell! ). This always seemed to happen at about 3:00am.

Finally got tired of messing with it and ordered the new rear furnace. Not long afterward the front furnace did the same thing so replaced it too.

see ya
ken

Re: Noisy Hydro Flame (Atwood) Furnace

Reply #20 – November 23, 2016, 08:45:52 am

Quote from: kenhat – November 23, 2016, 12:22:19 am

...then start making a farting noise...

Did replacing the furnace eliminate the noise, or are you still hearing it? If so, might want to examine your diet...

Re: Noisy Hydro Flame (Atwood) Furnace

Reply #21 – November 23, 2016, 10:28:28 am

Thanks for the info Ken... Too bad about the thermostat, but at least we would only need one

I wouldn't mind a separate heater thermostat though. Perhaps we will be able to hear what your's sounds like at the Q.
Don

Quote from: kenhat – November 23, 2016, 12:04:32 am

The one drawback to the 2-speed furnaces is the thermostat. You have to use Atwoods thermostat. It uses a non-standard variable voltage to switch between low & high speed. I had to send back both of my thermostats for replacement after they malfunctioned. (would start the fan but never light the burner or jump from low speed to high speed then back again) Atwood replaced them but took several weeks to ship them. The new thermostats have worked perfectly so may have just been a problem with the batch I bought. The other issue is that the thermostat costs about $180 apiece. So once out of warranty theres that.
see ya
ken

Re: Noisy Hydro Flame (Atwood) Furnace

Reply #22 – November 23, 2016, 06:12:10 pm

Quote from: Don & Tys (AKA acousticart) – November 23, 2016, 10:28:28 am

Thanks for the info Ken... Too bad about the thermostat, but at least we would only need one I wouldn't mind a separate heater thermostat though. Perhaps we will be able to hear what your's sounds like at the Q.
Don

I did some research and looked up their patents. I think the new thermostat sends 3 or 4 different voltages for different functions (Fan low/high and heat low/high). I'd really like to know for sure, but I'd have to get my hands on a thermostat or meet up with somebody that has one to measure voltages off the signal wire. I pondered putting a 2stage furnace in, but I'd like to keep my duotherm all-in-one thermostat working. There's ways around this....and it would easiest be to make it manual switch for second stage (which is my plan for my "conversion")

Another thing to note on installing a lower BTU/hr unit is that it may be smaller than the hole size in the RV. I was thinking the same thing, lower btu = lower noise and fewer amps drawn....but i want a slide in replacement without trim rings etc.

Re: Noisy Hydro Flame (Atwood) Furnace

Reply #23 – November 23, 2016, 07:23:18 pm

Quote from: Don & Tys (AKA acousticart) – November 22, 2016, 10:13:55 pm

Robert,
Which one did you go with? I notice that the 25,000/40,000 BTU model has a max current draw of 15 amps on high but the one that is 23,000/34,00 BTU unit is a little of over 11 amps on high. Would like the highest capacity possible with only one furnace, but we want the quietest possible unit that will do the job. The current single furnace is 35,000 BTU but sounds like a volcano erupting...
Don

I got the 25/40,000 BTU unit. I have a 34' FT so I only have one furnace and the Atwood 2 stage is doing a great job so far. It isn't quite as noisy as my old furnace when it is running in high mode but it very rarely does that.

@krush I think they have made improvements to the air box on the 2 stage units and I'm pretty sure that the fan motor moves quite a bit more air than the old unit when on high speed. I only think there are two different voltages that come off the thermostat: one for low fan speed and low burn and another for high fan speed and high burn. The circuit board assemblies are much more complicated on the 2 stage units. They include LED lights for troubleshooting and appear to be constructed much better than the old units. If you can deal with having a second thermostat, it is well worth it to replace the whole furnace.

Re: Noisy Hydro Flame (Atwood) Furnace

Reply #24 – November 23, 2016, 08:14:03 pm

Quote from: rsihnhold – November 23, 2016, 07:23:18 pm

@krush I think they have made improvements to the air box on the 2 stage units and I'm pretty sure that the fan motor moves quite a bit more air than the old unit when on high speed......

Here's the manual with all the common replacement parts http://manuals.adventurerv.net/Atwood-Mobile-Service-Training-Manuals-2007.pdf From what I see, the 2stage and single stage are the same but in the parts you mentioned (motor, fan wheels, gas valve, thermostat, boards). The wiring diagram shows it all and it makes sense.

I need to pull my furnace apart to inspect the parts (hey, it's nearly 20 years old) and replace the fan. So, I'll order the spare parts and motor after I disassemble.

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