First time flushing hi-eff boiler-what do I need to know?

dronic123

first of all, can someone help me identify this valve and tell me how to torn it. Do I have to buy a handle or do I use a wrench?

Alan (California Radiant) Forbes

Looks like all you need is a flat-bladed screwdriver. And from that drop down screw, you have a Viessmann boiler.

Why do you want to flush your boiler? It should not be flushed unless there's air or a clog you want removed.

hot_rod

is this a boiler or tankless water heater?

We’d hat brand ac nd model?

A pic from back a ways, to see all the piping below

dronic123

@Alan (California Radiant) Forbes : yes it's a Viessmann boiler and I thought that you needed to flush them annually or every 2 or 3 years to remove any of the rusty bits from the iron piping which might block the heat exchanger—no?

dronic123

Ironman

No, it shouldn’t be flushed unless there’s an issue that necessitates it.

Flushing introduces fresh water with more air and minerals. Not a good idea.

To protest the boiler from debris and such, a DIrt Mag should be installed in the return line

hot_rod

A device like this in the piping.

Think of it like an oil filter and magnetic drain plug on an engine. It filters to 5 micron, and a magnet pulls small ferrous particles, like magnetite, a .05 micron particle.

A small water sample from that valve in a clear glass, let it settle for a day, see what is in the water.

With iron pipe the oxidation layer helps protect ir. As long as the piping is not disturbed the rust and corrosion tends to stick to the piping.

If you want more info you can use an at home test kit, or send a boiler water sample to Rhomar, Fernox or other boiler treatment manufacturers for analysis.

dronic123

@Hot_Rod:

The installer did not install a dirt/mag sep. and the boiler has been running for 3 seasons at very light duty. It appears that I will be unable to get a tradesman to fix the piping [The only quote I was able to get was north of $30,000 CA to redo the piping and install the accessories -separators etc.] So I am feeling a little stronger now and am going to try a DIY, with a lot of help, I hope, from the forum.

Back to the flush. I have to disconnect everything and drain the system. I thought it would be a good idea to flush the boiler as everything will be open. The Viessmann manual calls for a "cleaning" annually /then as needed? AI confirmed it (for what it's worth), and suggested Oatley Hercules Sludge Hammer…; Hercules …Cleaner; and Oatley Hercules Haymaker Descaler. If I could get some real time advise on this service, I think it would be very helpful.

hot_rod

The anual cleaning is for the fireside of the boiler not the water side. Even that depends on how the boiler looks st the first service. In some cases you may go 2 or 3 years between cleaning.

The boiler manual may tell you what type of cleaner to use. I would not use a strong acid type.

Hydronic cleaners from Fernox, Rhomar and Adey are my suggestion

The have screw on aerosol cans now to inject the cleaner. Otherwise you need a fill/ purge pump

You need several flush valves in the correct location to flush and purge.

When it is all said and done add a conditioner and the fluid should be fine for years

hot_rod

Here is an example of a one piece fill/ purge valve, Webstone is one brand.

Also an example of a boiler water spec for stainless boilers. Check your water.

Alan (California Radiant) Forbes

The last time I clean a Viessmann HX, tech. support said the only chemical they approve is CitriSurf77.

But I wouldn’t bother unless you’re having heat exchange problems. It’s not like an on-demand water heater that’s continuously getting fresh water loaded with minerals that get deposited on the surface that needs to be removed.