i want to purge then clean my old system before i install new boiler

maybemark

I live in a house close to 100 years old. i 1st will purge my system,and get as much crud out of it as possible,then i have purchased Rhomar 2100. My system is an old gravity fed with a little 3" pipe, but about 250 ln ft of 2" pipe and i don't know how many feet of 1 1/4" pipe going vertical, and 1" pipe to radiators. i also have 14 radiators, several of them are very large. I also have a 35 year old way oversized boiler. My system i would think is filled with crud, but actually it still heats my house. What i need help on, the cleaner says 1 gal cleaner to 50 gal in your system, how would i know how many gals i have aprx. If i can get some feed back, that would be great. Also, do you think I should flush and clean my old system 2 times, because it's so old? And then when i put my new boiler in, clean it once, then put inhibitor in it?
Any thoughts and help are appreciated
Mark

maybemark

Another question comes to mind, when i put the proper amount of cleaner in the system, with an old house like mine, how long should i leave the cleaner in there, before i flush it out?

kcopp

Good questions. Purge and flush as much as possible before adding the cleaner. its not going to be easy sine gravity systems are so big that velocity in the rads are hard to develop. It would help to isolate each rad. Lot of work. Another thing I have noticed is that it helps to take all pressure off the system, drain, let it sit for a hours or so then fill and flush again. reason being if you keep all the pressure in the system the sludge says on the side of the pipes and will not fall off.
I would do all of this then add the cleaner. Talking w/ the fernox folks they say 2 weeks is really the max. After that it becomes less effective.

maybemark

Thanks kcopp
My thought was to turn off all the valves on each radiator, before flushing, then open one radiator at a time on 2nd floor, bleeding to make sure it's full, and do this to all radiators, then keep running the water until I see it getting clear. this is my thoughts, but this is not my proffesion and I am only thinking this would be best.
Am i on the right track?
And does anyone know, after i flush my system, how many gals do you think my system is. i don't have a water meter, i would be able to see how many gals it takes to fill up, but no meter.

Anyone have any idea how many gal of Rhomar I should add?
thanks
mark

maybemark

I was looking at my existing boiler, and there is really no place to to flush and drain.
I was looking glose at the boiler, i have an 1 1/4 union on the retunside before the pump, did i mention this was a gravity fed, converted to pump? Well, before the pump, there is a union and long nipple, take this out, put a tee and 2 nipples, and put an old ball valve with a hose bib adapter. Also on the outlet side, again 1 1/4 pipe, with a union near the boiler, do the same thing.
Am i on the right track?
Please, comments are much appreciated
thanks
mark

kcopp

You dont have a lot of choice. Either cut in a couple purge valves and drains or just wing it by doing a dump and fill.
As to the amount in your system you can start filling buckets and start draining or you can measure up piping and figure it that way.

Roy_2

Kcopp's got it right - either get a close estimate by filling buckets when you drain it or get a close estimate by measuring the pipe.
1/2" copper pipe holds .9 gal / 100' that doubles everytime you jump a pipe size 3/4" 1.8 gal/100' 1" 3.6 gal/100' and so on. This all just has to be close enough - not rocket science - best guess on the risers and rads is good enough. Fernox is the best stuff I have used since the old really good stuff is no longer available, it was toxic and did off a few people who were careless. Instructions say - dump 1 can of the aerosol for every 25 gals then run the system. You cannot overtreat. If the system is hot then run it a few hours up to 10 days - if it is not heating 3-4 days of circulating up to 10 days. After 10 days the chemical loses the ability to hold the crud in suspension. And you will be back to square one. I do not think you will need to isolate the radiators - you do want the chemical concentration to the levels and you do want the water circulating everywhere.
Flush the system until things run clear - a second dose will not hurt and will show you if most of the crud is removed.

The studies all show that cleaning the system can help your systems efficiency as much as 25%. So it is something that most everyone should do.

I doubt you have enough chemical now - the 2" pipe alone is close to 50 gallons. I would be surprised if you find the system is less then 100 gals depending on your rads.

One last word before I end this diatribe -
Water quality on the new boiler is very important test your water! Ph and hardness to make sure you are within the manufacturers specs. The inhibitor will help correct most of the problems you might find with the water.

Roy

maybemark

Thanks guys, I appreciate it.
I was thinking that my system might have never been cleaned, so, i was thinking of cleaning it 2 times, then cleaning it one time, after the the boiler is in.
i bought 4 gals. i won't have enough for what i want to do. It will probably take more than 2 gals to do the system, from how your talking.
i also bought 1 gal of inhibitor, i guess that won't be enough either.

Do you think it's a good idea to clean the new boiler with the new close boiler piping that will be installed? Or am i going to far?

as far as my water i live in chicago, the PH here is 7.8, so this should be good for the fill of the new system