Near boiler piping

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Old 10-31-08, 08:31 AM
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Near boiler piping

I have Weil-Mclain CGa-4 hot water boiler. I have a single zone.
I am install this boiler myself, to this point all piping has been done. Now I am finishing the return and feed line. I need help
understanding on where to install the diaphragm expansion tank.
I have been looking for pictures of an installed unit. In the manufacturer manual below on page 17 it just shows an arrow pointing to expansion tank. I need more help than what is shown.
http://www.weil-mclain.com/downloads...ilermanual.pdf.

Thanks
 
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Old 10-31-08, 03:08 PM
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The expansion tank should be on the suction side of the circulator pump. Other than that, it's not critical.
Doug
 
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Old 10-31-08, 05:44 PM
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A CGa4 Weil is being installed instead of taken out? Or is this used? The amount of extra NG one of these would go through compared to a modcon is staggering. This is 105 MBH in and 88 MBH out... and not even close in the shoulder seasons. Is it ovesized for the house's heatloss? If so, that's even worse.
 
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Old 11-01-08, 08:22 AM
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To reply by WHO I am installing a new unit. I am somewhat confused by the remainder of you reply. Need some clarity. Looking for picture of a CGa4 installed. Thank you
 
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Old 11-01-08, 08:28 AM
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Thank you Gilmorrie. I am trying to find a photo of the CGa4 installed
 
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Old 11-02-08, 05:55 AM
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Old 11-04-08, 01:17 PM
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Originally Posted by godlife View Post
To reply by WHO I am installing a new unit. I am somewhat confused by the remainder of you reply. Need some clarity. Looking for picture of a CGa4 installed. Thank you
It just seems like a bad choice in boilers for this day and age. That's my own bias.
 
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Old 11-04-08, 02:01 PM
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The only bad thing is it is chimney vented. Other than that is is OK. We are so stuck in this assumed high efficiency market that we don't see the forrest for the trees.
When we look at life cycle cost we are still further ahead with mid-efficiency (85-88%) non-chimney vented products unless it is large cast iron radiators or radiant in floor heat. I am not talking about chimney vented 80% units. Chimney's should go away. The savings is not in modulation or 95% as you may not be there much, but in proper sizing, piping and control strategies. The difference in 95% efficiency and 88% efficiency is about 7.4%. That is $74 per $1000. Look at more maintenance, more expensive parts where does it leave you. I am not going to talk about longevity as i do not think any boiler installed today should be here in 20 years due to future technology.
For savings add in proper sizing , piping and a good control strategy and the savings will be about the same with a mod/con or not. How many retrofit boilers today will work at less than 126 - 132? Thats where modulation stops around 8.5% CO2. When we can get the boiler flue gasses to dew point we can get another 9% of heat.
If they walked away with efficiency and fuel savings why after almost 20 years in Europe are they still less than 25% of the retrofit market instead of 100%. Why in the western US and Alaska are the applications changing to more CI radiation systems and radiant heat instead of every job?
I have see many installations and the difference is more the savings between the old boiler size and the new boiler size than anything. I actually had the advantage of seeing an over sized cast iron boiler (88%) removed after three months of operation and a new boiler of same except a different size, 3 sections smaller, and the fuel savings was 49%. This was an all radiant system. I can only judge by the testing I have done, job visits and un-biased testing from others. The proof is not in the cards that it makes much difference between mod/con or mid-efficiency as long as both are properly sized, piped, control strategies etc. The cost difference for installations are about the same with the additional controls with the cast iron products and the mod/cons are a lot lighter. With all that said will the mod/cons still work OK as a retrofit? Yes, but not at saving much more fuel.
Sorry about the rant again but you guys know I have to get it off my chest sometimes as I keep seeing everybody thinking they are getting 95% products when they are not due to water temperature.
 
 

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