How Do I Purge my Hydronic Heating System?????

Joey

I have a gas furnace and 2 zones for hydronic heat. I can hear a little gurgling in the pipes and I'm sure there is air somewhere in the system. Question is: How exactly do I purge each zone? Click the link below or copy and paste it for a sketch of my system, that might make describing easier. Basically, in order to purge each zone, which valves do I need to shut off and which stay on.

http://i120.photobucket.com/albums/o199/jfon0604/Furnace.jpg

How long do I run the water through the system? After its all said and done, what pressure should I put the system back up to.

Sorry for all the questions, I appreciate any help!

Thanks.

chris_93

purge system

Your system was installed with future service in mind. Lots of isolation valves are good!!
For zone 1>
1.Close valve 5
2.Open valve 1
3.use the quick fill on the feed valve #1.
4.Watch the pressure guage. Keep between 15-20 lbs.
5.Continue until air stops coming out of the hose.
6.Close quick fill, close valve 1 make sure pressure is between 10-12lbs. if not bleed off more water through valve 1.
7.Open valve 5 and your done.

Repeat for zone 2.
using valves 4 and 2.

Good luck.

Kal Row

simple...

-1- shut boiler

-2- shut valves 4 and 5,

-3- hook up a hose to bib above #4

-4- if your boiler's water feed pressure regulator has a lever, lift it straight up to pressurize the system but keep it below 25psi or the boiler's pressure relief valve will open - you might need to play with this lever up and down as you purge, remember the original pressure - the correct pressure cold is the highest point in the system - minus the lowest point in the system in ft divided by 2.33 + 5 - that should be your cold static pressure - eg if you system is 18ft tall, typical 2 story house - from boiler in basement to radiators at floor of level 2, then , 18ft / 2.33 = 7.7, + 5 = 12.7. “12.5” just happens to be the factory setting for most feed regulators, as well as the air pre-charge pressure, on expansion tanks
- the 2.33ft is because every 28inches of height is 1 lb of pressure, the +5 is to keep at least 5psi of pressure at the highest point to keep the pump from sucking in air

-5- open bib above #4 and drain on until water runs clear and quiet

-6- close bib and repeat for bib above #5

-7- drop feed bypass lever and drain any bib to bring pressure down to orginal level

-8- reopen valves 4 and 5

-9- restart boiler and have a nice day

For more detailed info – you will have to buy dan holohans books and really learn about the systems

Joey

Thanks so much your you help guys!! Quick question...does it matter if I shut both valves 4 and 5 at the same time to drain either zone? Or should I shut 5 and open bib 1, let it drain. Then open 5 shut bib 1. And lastly, shut 4 and open bib 2?

chris_93

You can shut them both together. Remember you are not draining the system you are replacing the existing water and (air) with new water via the feed valve.

Joey

Great!! Thanks so much for your help!