steam system questions

llydan

1. How often should I drain my boiler, I drain the low water cutoff every two weeks but the last engineer recommended that I drain the whole system while the engineer that serviced the system the time before said that was the worst thing you could do for a steam system. The worst thing is that they both work for the same company!



2. I have a radiator the keeps blowing water out of one of the vents. where possible I've checked that there is a return level for any condensate but cant get to all the piping. Every engineer who see's the radiators at first glance thinks that they are baseboard heaters but they are cast steam radiators. Should I create an expansion trap of some sort? I need to do something because it's ruining my floor!



Thanks for any advice

JStar

Vent

What pressure is the boiler running at? Do you have a picture of the problem vent?



I recommend flushing each drain for just a few seconds, once a week. And a full boiler drain and flush once every two months. The frequency depends on the water quality. Fresh water IS a bad thing, so you should always run the boiler for 15 minutes after adding fresh water to boil out all of the oxygen in the new water.

ChrisJ

draining

Jstar, you recommend completely draining a steam boiler and introducting 100% makeup water every two months?



I'm curious on other opinions on this matter.

nicholas bonham-carter

Proper boiler draining

The purpose of draining anything on the boiler is for flushing out, and removing sediment.

The lwco has a float inside whose action could be impeded by a pile of rusty flakes on the inside. Flushing it out will clean it out so it will work when it needs to.

Flushing out the boiler from the drain will wash out some of the calcium buildup.

Definitely run the boiler for a 15 minute boil after adding any new water.--NBC

JStar

Water

Makeup water is a necessary evil. If you run the system to boil out the oxygen right after you fill it, you'll eliminate the bad part of fresh water.

Dave in QCA

weighing in

You have gotten some very good advice so far and I don't disagree with any of it, with the exception of the advice you got from your contractor engineer and the technician, who obviously are saying the opposite thing.



It is important to remember that make-up water enters the system for one of two possible reasons.  The first, and most common is to make-up for lost steam or condensate.  Steam or condensate is lost because of leaks in the system.  A very small amount of water is lost through normal operation because during the venting process, that air coming out is quite humid, and over time, there will be a small loss of boiler water due to that factor.  This is normal.  Larger amounts of makeup water, because of system leaks will cause serious problems in the boiler.  This is because when you lose steam or condensate all of the minerals that were originally in the water remain in the boiler.  As you add makeup water you bring in more water and minerals, and the cycle continues.  If you have high chlorides in your water, this is a recipe to rot out a boiler in much less than its normal life.   The second reason for makeup water is to replace boiler water that has been dumped from the boiler.  Dumping portions of your boiler water will help prevent mineral buildup and as long as the makeup water coming in is brought to a boil right away, the makeup water poses little harm. 



Words of caution:  It is important to have a water meter on the makeup line so you know just exactly how much makeup water has been added to the system as a replacement to lost condensate or steam.  Otherwise, you operating in the dark and really don't know what is going on.   Unnecessary dumping of boiler water provides no advantage, and since oxygen rich, raw, makeup water is corrosive, you don't want to be continually adding it to an otherwise tight system that has not been losing any water except for the boiler water being dumped by the operator.  Critical point, if you drain a hot boiler and quickly refill it with cold water, you run a VERY high risk of cracking it!  The boiler must cool off a degree, and a boiler that is still warm should be filled very slowly.