Sears installed way too big boiler

Lineman

My old boiler was 62,000 BTU. We did the math and my house only calls for 37000 BTU Sears was to install a 90% efficient 50,000 BTU unit. They were having problems locating one of these units. They installed it yesterday and when I got home from work they actually installed a 100,000 BTU unit. Will there b any issues with having a larger unit?

Jean-David Beyer

Probably.

If your heat load calculaton was correct, and if you got and paid for a condensing boiler, you will find you get very low condensing, so your gas bills will be too high. If this is non condensing, you will probably still have problems with short cycling and excess cost.



You do not want to deliver milk with a fire truck.

You do not want to take your kids to school in a Formula 1 race car.



If Sears do not know the difference between the two boilers, what are the chances that they piped it correctly?

Lineman

Boiler

It is a condensing boiler. A Dunkirk q90-100. I paid for the q90-50

Ironman

Oversizing not Good

JDB is right. Oversizing a boiler by that much shows a lack of hydronics knowledge. Their intent may have been good, especially if your heat was out, but not a good choice from a design stand point. I"d tell them you want the correct size boiler installed.



Also, that boiler must be setup with a combustion analyzer.

Lineman

combustion analyzer.

Why do I need combustion analyzer?

Jean-David Beyer

Some contractors do not know their business.

The salesman at my former contractor had the same idea. He did not do a heat loss study. So I did. I got about 35,000 BTU/hour at 0F outside. He recommended a W-M Ultra 3, 105,000 BTU/hr. I insisted on the 80,000 BTU/hour (smallest) model. He said the one he recommended would modulate down to  21,000 BTU/hr (true) and give me more heat for when it really got cold. But with my load I would need the 35,000 only when it was 0F outside, and design day around here is 14F. And those loads would be only when both heating zones were calling for heat at the same time, which they rarely do. Gives turkey's a bad name.

Jean-David Beyer

I hope you do not.

I am not a contractor, and wonder if I need a combustion analyzer. I should not need to have one, because the contractor should have one, know how to use it, and use it.



My former contractor did not have one, and would not even follow the manufacturer'r instruction for maintenence. They said you did not need one at installation time because the burner is set up at the factory. But they would not use one for the annual service either. That is why they are my former contractor.



My new contractor did lots better, but they, too, did not use a combustion analyzer. There seem to be things that seem necessary, and it says so in the manufacturer's installation and maintenance manuals, but the contractors seem reluctant to do them.



So you may need to get one at some point, learn how to use it, and figure out what to do about the numbers it reveals. But you should not have to.

CMadatMe

Why Sears?

Why did you choose a retail store to install your boiler?



Oversized boiler gives you 3 problems. One, the oil or gas company says thank you for wasting the fuel you pay them for.Two, the service man will thank you for the extra ware and tear as your chances or providing him many service calls just increased. Three, the next installer thanks your current installer for providing him with a boiler that will not make it through it's life expectancy..

Mark Eatherton

Uh, yeah... That will be problem....

First off, ECR doesn't even make a 50K btuH condensing boiler.



http://www.ecrinternational.com/secure/upload/document/1631.pdf



Not sure who or why they are yanking your chain that direction, but... it does not exist.



Secondly, none of their condensing boilers modulates, so it will be short cycling like a Banshee, which is not good.



I'd recommend you have the installing company come back out and explain why they are driving a tack with a sledge hammer, and what they can do to rectify it. Otherwise, the appliance will have a shortened life expectancy due to the starting/stopping that it will be doing.



ME

Charlie from wmass

They have it listed here

http://www.ecrinternational.com/secure/upload/document/419.pdf They list a 50, 75, and a 100.

Mark Eatherton

Possibly old literature???

Mine is 10/08. Yours is 10/04...



HMMmmmm....



ME

Ironman

Q90 -100

Mark,



Q90 -100 is the series, but there is a Q90 -50 size. Just as the Q90 -200 series has a 125, 150, 175 and 200 size. A little confusing on the surface to say the least.



Also, the same block is used on all three sizes of the Q90 -100 series, just the burner is down-sized.



It may be that using Sears instead of a heating contractor has one up side, that being that due to their size they may be more willing to eat their mistake than some contractors are.

Mark Eatherton

Thanks Bob...

I learned something new today.



Have never used their products before, and was making some assumptions based on their literature.



I stand (sit?) corrected.



I would still recommend it be down sized unless it is doing DHW as well.





ME