Pinnacle (Munchkin) Vibrating

Tom Asaro

I have a Peerless Pinnacle 140 that was recently installed *correctly* thanks to the help I received here (it was piped incorrectly the first time around, but not fired up).

Anyway, now that it's been running for a few months, I have some questions:

1. Now that the weather has been a little warmer, the boiler might not fire up until the evening. The FIRST time that it does (I am assuming because the water is cold, but this doesn't really make sense) it makes a horrible vibrating noise for about 5 seconds. It really doesn't sound good. Any ideas on what could be causing this?

2. I have the potentiometer set to 180 degrees, but the boiler never makes water hotter than 155 degrees. The differential is set at 30 degrees, but that shouldn't matter if I am interpretting the manual correctly. If I have it set at 180, shouldn't it fire until the water reaches 190, then not fire again until it goes down to 150?

Any help is greatly appreciated! You guys helped me out in a big way the first time around.

- Tom

Cliff Brady

1 and 2

1. Could be a lot of things but I would look at how the PVC vent and exhaust are supported to see if you are getting a lot of vibration during the pre-purge. Mine pre-purges fairly audibly but not outrageously or abnormally so.

2. What max temperature do you need for your system? If no dhw you can lower it as far as you can and still stay warm with seasonal adjustments. This will maximize runtimes and modulating down. The behavior of the pinnacle is that it starts to modulate down at it approaches the setpoint based on supply and return temps (I think). It seems to stay at the setpoint unless the btu demand gets well under the lowest modulation point btu output.

Keep your eyes open for the rumoured Tekmar 263 that is expected in the future to control the modulation of the Pinnacles with a variable setpoint based on outdoor reset and dhw demand. Look at the literature for the 265 (3 staged modulating boiler control)from their website. This should help increase runtimes dramatically and reduce the number of pre and post purges which are often audible.

Tom Asaro

More specifically. . .

The vibration seems to come from inside the boiler itself, but I will re-examine the PVC. If this was the case, wouldn't it vibrate on EVERY pre-purge? It is only happening when the boiler has had a chance to "cool down". The fan sounds normal during pre and post purge.

My original heating contractor did not know what he was doing. To make a long story short, the amount of baseboard installed was designed to run at 180 degrees. It is not installed yet, but a Peerless Partner is on the way (which I believe asks for 180 degree water?)

J.C.A._3

The worst.....

Vibration I've heard from a Munchkin, thus far, was a almost unconnected "concentric vent kit". The installer neglected to glue the outlet/exhaust pipe to the inner hole in the rear completely.They work well with normal air, but don't run so good on recirculated exhaust gasses.

Another consideration, how long is the run for the vent/intake? We had to put a reducer bushing into the normal concentric vent, to keep the proper "back pressure" on the unit.It was on a very short (less than 2')run.

I believe a call to HTP is in order. They have some fine tech support! Let us know how you make out, and the repairs effected. Inquiring minds NEED to know!Chris

hr

Maybe something

got sucked into the blower. The least amount of imbalance will cause noise on a fan wheel. I've seen even small paper wrappers raise a fuss in a blower wheel.

Or the fan wheel, lose on the shaft.

Raise the hood and watch the fan carefully for more clues.

hot rod

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Tom Asaro

Not the PVC

It's definitely not the PVC as far as I can tell. And if it was, wouldn't it produce the vibration EVERY time? The noise only occurs when the boiler has not been running for a while (enough for the water in the system to cool down).

Anyone have ideas on why the temp won't go up to 180 - 190? I know the pinnacle has a sensor to tell what temp the water is returning at, but this shouldn't have an affect on how hot the system gets, does it?

- Tom

Guy_5

Vibration

Check the CO levels. If they are low (less than 80ppm) on high fire you can get a flame driven harmonic. Once the chamber is warmed and becomes a more hospitable enviornment, the noises will go away.
If you set the high fire CO to 105-110 PPM, the low rate will fall into place and the unit will operate quietly and efficiently.

Tom Asaro

Water Temp

Thanks Guy - I will ask my contractor to test/adjust the CO levels.

Any reason why the unit won't make water hotter than 155 degrees? The potentiometer is set at 180. I even tried setting it to 190 and 200 with no results.

If it's set at 180, shouldn't it heat up to 190?

jw

Short vents!

Have found that at very low fire, some of the munchkins will make a howling sound. Have found that it was because the vent was short and added some restriction with the addition of a reducing bell on the terminus. May have to do some experimentation with different bells.

The other reason they will "grumble" is if the water used to fill them had a load of minerals and some of them precipitate out on the HX which calls for an acid flush and refill of system with GOOD water. Some of my contractors use water hauled in from the local water softener folks. (culligan. Demineralized water)

jw

perhaps

Your system is sucking the BTU's out faster than the boiler can provide them? Is it BB or radiant? Is it one zone? Just thing to look at.