random flushing of heating system

butcherpete

Good day
I actually started a new job,
They have alot of sediment/scale (what be it) in the heating system.
They insist on blowing down their Y strainers, ( and anything else with a blowdown valve) unit water runs clear.
I told them they are introducing un-needed fresh water into their heating system, which is in turn creating more sediment/scale.
The boiler plant is 12 Aerco boilers, a mix of steel pipe and copper.
Many heat pumps, which the y strainers plug up often, and require more blowing down.
I suggested some water treatment.

Any help is appreciated

Inliner311

I could be wrong with this but I think people's concern with adding water usually is from losing water from not having a tight system. That leaves more minerals in the system because the water itself it being evaporated off. I'm not sure flushing the system is a major concern because you should be taking out more sediment and minerals than you are putting in. If it's a concern with your company's system, maybe you can have the water analysed. Both the water being feed into the system and the water being blown down. That will tell you if you are taking out more sediment and minerals than you are putting back in.

I think there is a fine line with water treatment because you want the water to be saturated enough with minerals so it isn't pulling from the pipes and the boiler but not enough that it's creating sediment. It might be more time consuming to find that point than what your company is currently doing.

I could be all wrong with this so hopefully someone with a better understanding of water will chime in.

butcherpete

Inliner311 said:

I could be completely wrong on this but I think most people are concern with adding water if a system is not tight and is losing water. Flushing the system is less of a concern since you should be taking out more of the sediment and minerals than you are putting in. If you are concern about it though maybe you can get the water being feed into the system analysed and take some samples of the blow down too to be analysed.

By water treatment, do you mean chemicals or something like a reverse osmosis system to clean the water before putting it in? Someone might chime in about how chemicals will help. I think you will have to do alot of tinkering on a reverse osmosis system to make sure your getting enough minerals into the system so the water isn't pulling it from the pipes and boilers. You could be causing a whole other set of problems if the water is too soft.

water treatment as in corrosion inhibitor.

I've never worked at a place that just randomly blew down strainers, until the water runs clear. ???

I'd ask, what is the point of an air seperator on a hydronic heating system, if not to get the air out?
Isn't that the point, to have an oxygen (mostly) free system, to prevent corrosion of your system. especially cast iron?

cashheatandactech1

in my opinion, if your system is big enough to be called a plant, then you need to be doing water treatment.

hot_rod

Sounds like a large system? The only way to flush heavy sediment, rust, dirt out is to get purge velocity thru the system up around 5 fps or higher. Just purging with fill valve flow, around 10 gpm, for instance, will not get the crud out. So little by little is comes to the y strainers.

So either get a large gpm purge pump and blast it out, or keep servicing the strainers.

The problem with constant flushing is you add O2 and minerals every time you put fresh water in, so the problem tends to grow not shrink.

Here is an example of flows need to to flush large pipes. So if you have 4" piping, you need to flow around 160 gpm to move out the heavy particles. A hydronic cleaner like Rhomar, Fernox, will help loosen up the crud also.

I learned about this large flushing challenge years ago from this company PurgeRite www.purgerite.com at a GEO show. They travel the country purging large, problematic jobs and can flow 24" piping at velocities high enough to move crap out of the lines and equipment.

butcherpete

hot_rod said:

Sounds like a large system? The only way to flush heavy sediment, rust, dirt out is to get purge velocity thru the system up around 5 fps or higher. Just purging with fill valve flow, around 10 gpm, for instance, will not get the crud out. So little by little is comes to the y strainers.

So either get a large gpm purge pump and blast it out, or keep servicing the strainers.

The problem with constant flushing is you add O2 and minerals every time you put fresh water in, so the problem tends to grow not shrink.

Here is an example of flows need to to flush large pipes. So if you have 4" piping, you need to flow around 160 gpm to move out the heavy particles. A hydronic cleaner like Rhomar, Fernox, will help loosen up the crud also.

I learned about this large flushing challenge years ago from this company PurgeRite www.purgerite.com at a GEO show. They travel the country purging large, problematic jobs and can flow 24" piping at velocities high enough to move crap out of the lines and equipment.

I agree, constant flushing makes the problem worse, not better.
Try telling the (non plumber) guy that is here, that has been running "plant" for last 7 years.

SuperTech

Sounds like the plant would benefit from the installation of an air and dirt separator, like the Caleffi Discal Dirtmag.

HEATON

amen &amen