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Best Practices:

Success starts on the mechanical side


Having the right mechanical equipment is the first step on making it right. You will save on water treatment and protect your multi-metal, closed loop hydronic systems.

The Basics

The Basics

Water Treatment

Preserve the long-term, high efficiency operation of the condensing boiler


Focus on adjusting the system pH in accordance with the water quality standards and inhibiting corrosion within the piping system.


The Tannin Guys® tannin-based water treatment is proven to protect the integrity of the boiler and preserve its operating efficiency.


Operating hydronic system outside the optimal pH range can lead to boiler failure


The corrosiveness of the process water and stability of the corrosion-resistant layer in multi-metal closed-loop systems are strongly dependent on the process water pH.


closed loops must be pre-cleaned before treatment is initiated


Initial construction of any closed loop will introduce contaminants into the system. System pre-cleaning will remove flash rust, dirt, and any oil and grease.


In a retrofit closed loop system, pre-cleaning will remove any old deposits and new contaminants.

The Essentials

The Essentials

Water Flow Meter TGWT

Water Flow Meter

Key indicator of leaks: annual make-up rate should not exceed 10% of the total hydronic system volume


A water meter installed on the cold water make-up line allows the maintenance staff to monitor for system leaks and lost chemical treatment.


Water flow meter can also be used to estimate the total volume of the system during the initial fill.

Air Vent TGWT

Air Vent

Against corrosion: air separators will reduce the dissolved oxygen level introduced from the cold water make-up


High levels of dissolved oxygen will accelerate failure of the boiler or other system components due to corrosion and oxidation.


Use air separators, preferably tangential or micro-bubbler styles, with an automatic air vent installed.

Stainer TGWT


To protect heat exchanger: strainers will minimize erosion, flow obstruction, and lost heat transfer


Standard mesh strainers (maximum 20 mesh) installed on each boiler’s return (inlet) piping will protect the boiler from large particles and debris entering.

Bag Filters TGWT


Keep the system clean:
should be designed for 10% of the total system flow


The side-stream filter is the preferred method. Use cartridge filter or bag filter to collect the suspended particles in the system.


Quick example for sizing:

1,000 gpm system flow =

100 gpm side-stream system

Clean system:

5 or 10 microns (2500 to 1250 mesh)

Cartridge Filters TGWT

Filtration (cont.)

New closed loop system

contains some particulate matter from the construction: dust, dirt, rust, weld slag solder flux and metal shavings

Micron/Mesh sizing recommended

High contaminant level:

25 or 50 microns (550 to 270 mesh)


Retrofit closed loop system

may contain oxidized steel / iron particulates


Micron/Mesh sizing recommended

High contaminant level:

25 or 50 microns (550 to 270 mesh)

Valves TGWT


Use them: drain or purge the hydronic system without routing concentrated water treatment chemicals or debris into the boiler’s heat exchanger


Manual isolation valves installed on each boiler’s return (inlet) and supply (outlet) piping allows the user to hydraulically isolate the boiler from the system.


It should be standard practice when flushing or adding concentrated water treatment chemicals.

Clever Options

Clever Options
Corrosion Coupons Rack for Water Treatment TGWT

Corrosion Rack

Help to prevent failure: different corrosion coupons alloy are available for your closed loop


Aluminum, Copper, Mild Steel, Stainless Steel, etc.

Magnetic Rod

To increase filter bag lifetime

For closed loop with a lot of suspended iron particules, using bag filtration

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