Big (for me) service is coming up - please validate my plan of attack!

Reply

  #1  
Old 03-04-13, 07:56 AM
_
Member
Thread Starter
Join Date: Dec 2010
Location: USA
Posts: 332
Received 0 Votes on 0 Posts
Big (for me) service is coming up - please validate my plan of attack!

Iím eagerly awaiting the end of heating season to perform some services on my hydronic system with an old Repco LA100c gas fired cast iron boiler. The system is 30 yo and Iíve been a proud owner of it for last 3 heating seasons.

Currently I have 2 problems:

1. My pressure reducing valve (PRV) is broken (thread).
2. I believe I have kettling going on (thread).

Here is my plan.

0. Shutdown the system and let it cool to ambient temp.
1. Connect garden hose to boiler drain, open intake valve, press down on PRV to let as much water and as fast as I can and let it rip to flush as much sediment as possible.
2. Repeat step 1 but use zone 1 drain.
3. Repeat step 1 but use zone 2 drain.
4. Bring system pressure to zero.
5. Check expansion tank, adjust pressure if needed, replaced the tank is needed and install a ball valve and a drain for future maintenance if Iím replacing the tank, if not leave it alone Ė I want to be as non invasive as possible with an old system.
6. Open PRV body and possibly pry open the diaphragm to let as little water as needed to drain from the system. By doing this Iím trying to let in as little air in as possible, but this might not make sense so this is optional step.
7. Remove PRV from the system and use the opening to add 1 gallon of Rhomar Hydro-Solv 9100 Boiler Treatment cleaner.
8. Put new PRV back, add make up water, run system hot for few hours, check new PRV function, system pressure, etc.
9. Shutdown boilerís pilot and run system cold for half an hour every day or so for 4 weeks.
10. Flush the system until water PH matches PH of fresh intake water.
11. Shut down the system until new heating season.

So my questions are:

1. Do these steps make sense? Am I missing anything or plan on doing wrong?
2. Step 7 for people who used this system Ė should I dose the treatment and do it several times instead of all at once?
3. Is there anything else I should check/do/replace while my system is drained and I have this opportunity?
 
Sponsored Links
  #2  
Old 03-04-13, 09:20 AM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
6. Open PRV body and possibly pry open the diaphragm to let as little water as needed to drain from the system. By doing this Iím trying to let in as little air in as possible, but this might not make sense so this is optional step
Please explain this step a bit more... "...pry open the diaphragm..." I don't understand what you are trying to accomplish.

I think we need to clarify acronyms...

PRV can mean two very different things:

1. Pressure REDUCING Valve

2. Pressure RELIEF Valve

In most cases it's best to type out either REDUCING or RELIEF valve...

7. Remove PRV from the system and use the opening to add 1 gallon of Rhomar Hydro-Solv 9100 Boiler Treatment cleaner.
I believe that you want to add the schtuff into the pressure RELIEF valve opening.

9. Shutdown boilerís pilot
Leave the pilot lit, turn the gas valve so only the main burner is off.
 
  #3  
Old 03-04-13, 10:47 AM
_
Member
Thread Starter
Join Date: Dec 2010
Location: USA
Posts: 332
Received 0 Votes on 0 Posts
NJ Trooper,

it's pressure reducing valve, I actually spelled it out right away:


1. My pressure reducing valve (PRV) is broken (thread).
and then used PRV for the rest of the post.

as for PRV diaphragm, let's forget about that, i will remove the PRV. originally i thought i might just replace the guts of the PRV with the new ones, but it's not longer relevant since i want to do chemical cleaning and other reasons. which brings me to your next quote:

I believe that you want to add the schtuff into the pressure RELIEF valve opening
the way my PRV (reducing not relief) is positioned in the system, removing it would allow me direct access to the pipe that goes right down to the boiler, so i will simply pour the cleaner thru that opening into the boiler, no need to unscrew the pressure relief valve.

Leave the pilot lit, turn the gas valve so only the main burner is off.
i turn the pilot off for the summer.
 
  #4  
Old 03-04-13, 04:21 PM
T
Member
Join Date: Jun 2012
Posts: 986
Received 13 Votes on 11 Posts
I would pump the Hydrosolve into it now and finish off the heating season with it in. The 9100 works better on a hot system. It will also circulate throughout the radiant section of the system and get it cleaned up as well. Do the flush and repair towards the end of the season, allowing some run time so your fresh fill becomes somewhat inert.
 
  #5  
Old 03-04-13, 05:38 PM
_
Member
Thread Starter
Join Date: Dec 2010
Location: USA
Posts: 332
Received 0 Votes on 0 Posts
tom, i don't want to do any work on a system right now and without removing anything i have no means of adding it to the system.

we have a baby and i don't get much time to work on things continuously so i do everything piece by piece. plus i don't want to risk being without a heat either. when heating season is over i have luxary of taking my time.

i do understand that the cleaner works better at higher temp so i plan on letting it do some work while boiler is firing for a few hours, the rest would have to be at ambient. maybe i will leave it there for longer than 4 weeks to compensate for it.

the solution is slightly alkaline and it will work better at higher temperature, but it will also be less aggressive at lower temp so i could leave it there longer to do its deed.

maybe i will get in touch with a manufacturer on this. currently their instruction say to run it for few hours hot and then flush it. that's what i'll do anyway. keeping it there longer is a bonus, i think.
 
  #6  
Old 03-05-13, 05:44 AM
T
Member
Join Date: Jun 2012
Posts: 986
Received 13 Votes on 11 Posts
Diver, is there a drain on the boiler that looks like an outdoor faucet? If so, that's where you can add without taking anything apart. All you need is a small pump and a 5 gallon bucket. If you have that access I can step you through it, take ya 5 minutes. Then let it do its thing over time. Being its a 30 year old boiler, you would benefit from the heat and extended time that its in your system.
i also recommend using Rohmars 922 corrosion protection with your new fill.
 
  #7  
Old 03-05-13, 07:56 AM
_
Member
Thread Starter
Join Date: Dec 2010
Location: USA
Posts: 332
Received 0 Votes on 0 Posts
tom,

did you drain your system before adding the solution? or is pump enough to overcome the pressure in the system?

i wonder if i could use a pump, connect the hose, turn the pump on and open the drain and let the pump force the solution in and close the drain before the pump runs out of the solution?

i have a small submersible pump that i use to pump the rain water of the pool cover, i wonder if i could use that.
 
  #8  
Old 03-05-13, 08:01 AM
_
Member
Thread Starter
Join Date: Dec 2010
Location: USA
Posts: 332
Received 0 Votes on 0 Posts
i think i'd need something like this: Portable Utility Pump - Save on this Portable Utility Pump

but i wonder if i can get a gallon of the cleaner, pour it into a narrow vessel and place a submirsible pump in it and pump it until until the level goes almost to the bottom of the pump.
 

Last edited by _Diver; 03-05-13 at 08:27 AM.
  #9  
Old 03-05-13, 08:39 AM
_
Member
Thread Starter
Join Date: Dec 2010
Location: USA
Posts: 332
Received 0 Votes on 0 Posts
for Rohmars 922 corrosion protection - did you use their test kit to get to the desired ppms? or did you calculate the volume of the system liquid and figure out how much protector to add?

suggested 7.5-9 pH levels seems overly alkaline. high alkalinity with high temperature will drive calcite saturation index (CSI) way up which will make it prone to scaling.
 
  #10  
Old 03-05-13, 12:15 PM
T
Member
Join Date: Jun 2012
Posts: 986
Received 13 Votes on 11 Posts
Diver, I drained off enough to bring the pressure down to just about zero. I used a pump like this placed in a 5 gallon pail full of water mixed with the cleaner.
Superior Pump 91250 1/4 HP Thermoplastic Submersible Utility Pump - Amazon.com

To get the mixture into the system, I opened a bleed valve on one of my zones then opened the drain on the boiler with the pump connected using a washing machine house (double female) and plugged it in. It was really easy to do. After your done, close the valves and bring the system pressure back up.

After 5 - 6 weeks I flushed it out really good then did the same process to add the gallon of 922. I did not use their PH strips to check the system.

I'm probably a bit over on the 922, but I was told it wouldn't hurt anything.
The 922 is really deep blue, my system fill looks like Caribbean sea water and the system is completely silent once again. The kettling was going on for just over 2 years, drove me nuts. Worked for me, I hope it does the same for you.

I
 
  #11  
Old 03-05-13, 12:56 PM
_
Member
Thread Starter
Join Date: Dec 2010
Location: USA
Posts: 332
Received 0 Votes on 0 Posts
Tom,

Thanks for your response. I had a chance to think about it, and now I agree with you that it would make sense for me to do this before the upcoming maintenance.

I have a similar pump so I think I could use it the same way you did. First I was thinking that I would just bring the pressure down to zero and try to pump 1 gallon of the cleaner (not diluted) in with the rest of the valves closed. But now I think that it would probably be too much for the expansion tank to take and it would blow the pressure relief valve.

So I should probably try do it in stages Ė connect the pump to boiler drain, keep the rest of the valves closed. Turn the pump for a bit and let it run until boiler pressure goes say to 20 psi (could be seconds?). Shutdown the pump, let the water out from a different drain valve and bring it back to 0 psi. Repeat until solution is all in, then either reduce the pressure to nominal or add water to bring it to nominal.

What do you think? How long did it take for the pump to push it all in?

I will calculate the system volume tonight to figure out how much of 922 I would need. I donít want to get too much of it in.
 
  #12  
Old 03-05-13, 01:29 PM
T
Member
Join Date: Jun 2012
Posts: 986
Received 13 Votes on 11 Posts
Diver, It takes less then a minute to pump in 5 gallons of water/cleaner into the boiler, do it in one shot. Do you have drains/bleeders for each zone? Open a zone bleed valve and pump through the boiler. The object is to push the mixture into the boiler. Your only displacing 5 gallons of system water.
 
  #13  
Old 03-06-13, 10:13 AM
_
Member
Thread Starter
Join Date: Dec 2010
Location: USA
Posts: 332
Received 0 Votes on 0 Posts
Tom,

The reason Iím somewhat hesitant to open a drain valve while pumping the solution thru another one is that I think the moment I open that valve it would start draining the water and letting the air in. Starting pump right away would hopefully push the air out and then itís a question of closing things at the right moment. I only have an boiler integrated air scoop and I want to avoid the need to test if it itís working effectively or not.

I could connect a hose and take it outside and elevated it. It would create a trap and allow for only some water to drain and it would not let any air in. This way I can pump in all I need and then close it up. I will figure it out.

I calculated the system volume and it came up with a surprisingly low number. I have baseboards on 2 levels Ė 1st and 2nd floors of my house. The dimensions of the house are 26í*38í. The vertical runs are 9.5í each floor. Overall it comes out as 307 linear feet of ĺĒ pipes. Which is about 8 gallons. Add a boiler, expansion tank, some pipe runs I donít see or not account for and itís about ~12 gallons. I thought it would be a bit higher.

I saw somewhere on Rhomar site that the cleaner is for systems up to 50 gallons. I guess I could still use a gallon of the cleaner for my system.

I do not see any recommendation for corrosion protector dosage. They say 30-60 ppm but do not clarify of what. I assume itís of whatever their test strips test. Itís definitely not of the cleaner itself since 30-60 ppm would require a minuscule amount of the solution. Do you happen to know the recommended amounts? Was it on the bottle by any chance?

Thanks.
 
  #14  
Old 03-06-13, 03:58 PM
_
Member
Thread Starter
Join Date: Dec 2010
Location: USA
Posts: 332
Received 0 Votes on 0 Posts
Tom,

I contacted the manufacturer regarding the dosage of the corrosion inhibitor, but haven't heard back from them yet.

I also noticed on their instruction page for the kit (pint bottle of cleaner, inhibitor plus strips) they mentioned that a pint size of either is good for system up to 25 gallons:

The Hydro-SolvTM 9100 and PRO-TEKģ 922 pint bottles are formulated to treat a standard residential system of up to 25-gallons in volume. For larger volume systems, additional product can be purchased from your local supplier or by contacting Rhomar Water Management at 1-800-543-5975
you mentioned earlier that a pint is not enough. is your system large then 25 gallons? mine appear to be about 12, so i'm thinking a pint might be just right for me. any specific reasons you felt that a pint was too small?

thanks!
 
  #15  
Old 03-06-13, 04:20 PM
T
Member
Join Date: Jun 2012
Posts: 986
Received 13 Votes on 11 Posts
Diver, I've got a 3 br. 2 story cape, baseboard heat. My guess is its about the same size system as you. When I spoke to the rep at Rohmar he said not to worry if I was over on the 922. I actually have the pint kit but didn't use it. It came with the PH test strips and all. If you want it, PM me.
i think your concern with air should be addressed. Simply adding water to the system will introduce air into the system. Air is part of water and needs to come out as the system stabilizes. Does the air scoop have an automatic air vent on it? If so, that needs to operate. Make sure the cap is loose and try to depress the schrader valve, yo should get a slight amount of water.
 
Reply
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: