Slantfin 90k btu boiler question


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Old 03-20-18, 07:11 AM
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Slantfin 90k btu boiler question

Hello everyone, I’m a newbie here. I’m a retired contractor and master mechanic. I’m fairly new to boilers and only have 3 years maintaining mine in my 1350sf cape cod style home with upstairs and dormers. My Slantfin 90k btu hot water propane boiler has four zones, zone one water heater, zone two livingroom, zone three master bedroom and master bath including a half bath and the fourth zone upstairs.
i primarily heat the home with a wood stove because the wood is free and use the boiler for hot water heater and backup heat. I keep the three zone thermostats at 62*.
My upstairs normally runs 3* cooler in winter and a couple degrees warmer in summer.
the bladder tank seems functional, hot on top, cold on bottom & tapping on it reveals hollow thud on bottom and saturated thud on top.
Bleader cap loose and seems slightly damp from bleeding. It does seem mounted low to me though, as boiler is in my crawl space.
Pressure is 25 psi at full operating temperature with all three heating zone running.

My question, Is this condition below normal?
When the upstairs zone comes on in early am, I hear what sounds like air in the copper pipes running up and down the ground floor walls to the upstairs radiators. After system runs a couple minutes and stabilized the noise goes away..
always heats and has never air locked, bled several times but not much air coming out bleeder.
sorry for the long post!

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Last edited by PJmax; 03-20-18 at 10:15 AM. Reason: reoriented picture
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Old 03-20-18, 09:46 AM
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k,
The 25psi is a little higher than what your need but as long as it stays under 30 is not dangerous. I like to run between 18-20psi.

What is your cold start pressure. It shouldn't vary more than a couple of lbs. between hot & cold.

When water is heated and delivered to the emitters (rads or baseboard) your copper pipes may expand a little when the hot water is first delivered creating a sound for a few seconds and then quiet down depending how the pipes were installed.

Could that sound you are hearing be expansion instead of air. Just a thought.

You want to bleed as little as possible so you are not constantly introducing fresh water which brings air into the system.

Hope this helps a little.
 
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Old 03-20-18, 09:54 AM
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The cold water pressure is around 17-19 psi. The noise I’m hearing isn’t the copper pipes or radiators expanding, its water rushing with gurgling sounds. The system may sit a week or two until it’s needed and used.
In October I serviced, bled and added water trying to hit 24 psi (serviceman who educated me pressure recommendation) but the automatic valve and pressure regulator added quicker than I thought it would.
Thanks
 

Last edited by k7iou1; 03-20-18 at 10:38 AM.
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Old 03-20-18, 10:37 AM
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Is the air bleed in the wrong location? Shouldn’t it be above the bladder tank above the water fill inlet? See pictures. Thanks!
 
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Old 03-20-18, 12:45 PM
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I suspect after reading the sticky on expansion tank pressure and the comment of couple psi difference with cold boiler and hot boiler my expansion tank lost its pressure. The house is going on 13 years old and I’m positive the pressure has never been checked. So I’m thinking of just installing a new tank with valves, gauge and drain so it can be checked periodically. Thoughts?
 
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Old 03-20-18, 03:03 PM
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The only vent I see is the one on the boiler which is correct as far as it goes.

Your extrol is connected to a regular tee and you would be better off with a Spirovent or Airscoop. That will automatically release any unwanted air before it gets into the lines. At least that's the idea.

That boiler vent is only good when you're filling the boiler initially. You need the Spirovent otherwise.

http://www.supplyhouse.com/Spirother...weat-9307000-p

http://www.supplyhouse.com/Taco-432-...coop-3513000-p

http://www.supplyhouse.com/

If you go to the sight above you can see your options. Click on HEATING and then AIR ELIMINATORS to see what is offered. I would go with the S.V. if possible.

The airscoop requires another taco vent on top.

http://www.supplyhouse.com/Taco-400-4-1-8-Hy-Vent
 
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Old 03-20-18, 04:08 PM
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Not sure the Spirovent will work with my circulator location. See diagram.
looks like I can relocate water feed and raise air vent.
I think I will replace expansion tank and install a ball valve with bleeder above tank for servicing. Close valve, open bleeder to relieve water pressure and adjust air pressure in tank.
 
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Old 03-21-18, 06:01 AM
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Expansion tank companies state tanks loose 1 pound of air per year. Normally shipped at 12 psig. After 13 years k7iou1 should be at zero psig. See procedures for setting tank pressure.

Boiler pressure temperature gauges are notoriously inaccuracte This would be good time to install a better, second gauge. Put it where can be read while adjusting pressure.
https://www.supplyhouse.com/sh/contr...%20psi%20gauge

I do not accept that all of air at highest points in system will get back down to boiler level vent. Put $5 auto vents at highest point of each zone. Around my boiler there are no air scopes, or other air removal gadgets. Nature takes its course, air rises in water and vents on zones work.

The Watts auto vent below can be opened for maintenance. Other types are throw aways.
https://www.supplyhouse.com/Watts-05...Vent-3679000-p
 

Last edited by doughess; 03-21-18 at 08:17 AM.
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Old 03-21-18, 10:27 AM
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Don't understand why you think S.V will not work for you. Just replace the tee with the S.V.

If it's because of the pump location it makes no difference at all. You can feed the boiler any place you want, that also makes no difference. I happen to feed my own boiler in the pipe where your vent is. On that nipple coming up I put a tee and then another nipple and coupling for the vent.

That one small vent is not made to bleed the whole system, just to help with the air from filling the boiler. It doesn't have the capacity.

As far as venting the high points of the system. We used to do that years ago but got away from it because it caused as much trouble as it helped. If that vent starts to fail as they all do over time besides venting air out when the pump came on it could also suck air in, bringing air into the system.

Everybody has different experiences with what works for them, mine happens to be trouble with venting high points never really worked any better than no vents.

As for your expansion tank, it's a good idea to check it periodically and isolate for service, but 12 years is not a long time for a tank. I have had the same tank since 1984 when I put the boiler in and have never touched it and is working fine. I'll grant you it's probably a rarity my point is because the book tells you something it doesn't make it so.

Just my thoughts but you can do whatever you are comfortable with.
 
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Old 03-21-18, 11:14 AM
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I guess my concern is in the instructions for the circulator location. See attached from the brochure. The recommended location is the hot side of the boiler but before the circulator.
thanks for all your suggestions!
 
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Old 03-21-18, 12:09 PM
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Although today's recommendation if possible is the supply side for the pump, it has been on the return side for 50 years and worked fine. Commercial jobs always installed pumps on supply, residential really doesn't make that much difference.

Since the expansion tank is the point of no pressure change if you put the pump after it you get a little more pressure, for lack of a better word, through the system.
 
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Old 03-22-18, 07:33 PM
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Spott : As far as venting the high points of the system. We used to do that years ago but got away from it because it caused as much trouble as it helped. If that vent starts to fail as they all do over time besides venting air out when the pump came on it could also suck air in, bringing air into the system.

The air valve washers in old style Jacobus-Maid-O-Mist vents started leaking after a couple of years. Jacobus is sealed unit and cannot be serviced. To stop leak people just tightened tire cap which also stopped auto venting. https://www.supplyhouse.com/Jacobus-...-1-8-Auto-Vent

The newer bronze body WattS-Automatic-Vent-Valve is very reliable and can be opened for servicing. https://www.supplyhouse.com/Watts-05...Vent-3679000-p

If the pump "vacuum" sucks in air it will vented by one of the auto vents.

I have 12 of the Watts and none have gone bad. This is another case where new generation products are better than the old.
 

Last edited by doughess; 03-22-18 at 07:58 PM.
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Old 03-23-18, 07:00 AM
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Will the 1/8” FV4 Auto air vent fit where the bleeder screw is in the to of the El fitting?
see picture.
thanks.
 
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Old 03-23-18, 07:18 AM
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Yes, that elbow has 1/8" female thread. The autovent label " 1/8 FV " identifies the male thread size.

Pictured is 3/4" sweat elbow with 1/8" female thread port with manual vent valve.

That elbow was designed for baseboard heating elements enclosures where this is little room for vents.

In boiler area with plenty of room the pick a place where air is likely to accumulate. Instead of that elbow use a tee with a couple of inches length of 3/4" copper on top as accumulator.

HomeDepot used to carry those elbows but stopped.
 

Last edited by doughess; 03-23-18 at 07:55 AM.
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Old 03-23-18, 10:07 AM
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Thanks for all the advice. Ordered parts today and Supplyhouse met another online site pricing for the Spirovent VJS125 $115
lve always enjoyed ordering from them!
regards
 
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Old 03-24-18, 08:45 AM
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Getting air out of hydronic system is very basic. Vent it.

The $5 to $10 autovents do the same thing as a $100+ Spirovents … vent air.

https://www.supplyhouse.com/sh/contr...NG=auto%20vent

Yes, some Spiro's have expansion area to facilitate air separation but a section of larger tubing/pipe will do the same things. Basic physics.

Basement boiler level venting is not the ultimate answer. Auto venting from upstairs elements is very effective.

A upper level $6 vent is worth it and saving $100 is always nice.
 
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Old 03-28-18, 05:49 AM
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I read somewhere not to use silver solder when installing the Spirovent. What type of solder do you use? Thanks!
 
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Old 03-28-18, 06:51 AM
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I have never heard that before and couldn't find any mention of it in the Spirotherm installation instructions. We've just always used silver solder without any problems.

Where did you see this.
 
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Old 03-28-18, 09:38 AM
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k7iou1: I read somewhere not to use silver solder when installing the Spirovent. What type of solder do you use? Thanks!

For domestic copper water fittings use lead free “soft solder”.

For health/safety reasons solder for human water and food applications cannot contain lead.

Silver solder for brazing needs temp over 800F and used for higher pressure and temperature applications like air conditioner refrigerant lines.

Below is link with many types …. lead free, lead, silver. Use a 95/5 lead free.

https://www.supplyhouse.com/Solder-430000
 
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Old 03-28-18, 03:09 PM
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K,
All you need is 95/5 solder. I am assuming that is what you called silver solder.

http://www.supplyhouse.com/Generic-S...mony-4060000-p

Sterling Lead Free Wire Solder (1 lb. Spool)
 

Last edited by spott; 03-28-18 at 03:41 PM.
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Old 03-28-18, 07:57 PM
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Can’t find where I read not to use silver bearing solder. Thought it was in one of their brochures. This is what I have but not sure of the content.
https://m.lowes.com/pd/BernzOmatic-3...older/50126493
 
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Old 03-29-18, 10:18 AM
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K,
That's fine. Just make sure everything is clean and fluxed and have a torch that produces enough heat and you'll be fine.
 
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Old 04-13-18, 12:01 PM
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Installed the Spirovent, Extol, ball valve with bleeder. The Extol was bad, no pressure and wouldn’t hold pressure. Good thing I ordered one! :-)
The Pressure gauge I installed reads 20psi and boiler gauge 25psi!
Ended up with 2 gallons extra “drained” fluid. Also the system looks like it needs flushing and I need to replace an 1-1/4 reducing tee this summer. I suspect there is a sealer added to the water-antifreeze mixture. Looked like sand but felt fibrous.
Capacity estimating? 4 zones, one upstairs, 1350sf, 90k boiler with 1-1/4” feeders & returns and 3/4” runs.
Which brand of antifreeze do you like? I need to place another order at SupplyHouse for the complete rubber kit for the Watts supply valve.
regards!
 
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