{"id":4990,"date":"2025-07-17T08:59:57","date_gmt":"2025-07-17T00:59:57","guid":{"rendered":"https:\/\/www.shopvalves.com\/?post_type=product&#038;p=4990"},"modified":"2026-03-24T10:51:16","modified_gmt":"2026-03-24T02:51:16","slug":"spirax-sarco-kbv21","status":"publish","type":"product","link":"https:\/\/www.shopvalves.com\/en\/product\/spirax-sarco-kbv21\/","title":{"rendered":"Spirax Sarco Spirax Sarco KBV20\/KBV21 Manual Boiler Drain Valve"},"content":{"rendered":"<p>The Spirax Sarco KBV21 manual boiler drain valve consists of a carbon steel ball valve with a reinforced PTFE seat and a stainless steel handle. The manual handle is available as a standard handle or as an extended \"T\" handle and is supplied separately from the standard and T handles. The handle cannot be removed when the valve is open and can only be removed when the valve is closed to ensure compliance with boiler codes. This boiler drain valve has been specifically designed for boiler draining, and is particularly suitable for systems that do not need to be drained on a regular basis.<\/p>\n<h3>appliance<\/h3>\n<p>Especially designed for boiler draining, especially for systems that do not require timed draining, see also information on timed systems.<\/p>\n<h3>Product Features<\/h3>\n<ul>\n<li>Designed for boiler discharge applications<\/li>\n<li>Suitable for boiler pressures up to 17.25 bar g, 208\u00b0C<\/li>\n<li>Size range DN 25 - 65<\/li>\n<li>The handle can only be removed when the valve is closed<\/li>\n<\/ul>\n<h3>Sizes and pipe connections<\/h3>\n<p>DN25,32*,40,50,65. Flanged, BS4504 PN40 or BS1560 Class 300. *DN32, PN40 only.<\/p>\n<h3>restrictive condition<\/h3>\n<table>\n<thead>\n<tr>\n<th>Maximum permissible pressure<\/th>\n<th>17.25 bar g at 208 \u00b0C<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Cold test pressure is<\/td>\n<td>60 bar g (PN40)<br \/>\n78 bar g (class 300)<\/td>\n<\/tr>\n<tr>\n<td>Seat leakage test<\/td>\n<td>6 bar g (air, water)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h3>material (that sth is made of)<\/h3>\n<table>\n<thead>\n<tr>\n<th>Part<\/th>\n<th>material (that sth is made of)<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>valve body<\/td>\n<td>Carbon Steel ASTM A216 WCB<\/td>\n<\/tr>\n<tr>\n<td>Seat and stem seals<\/td>\n<td>Reinforced PTFE<\/td>\n<\/tr>\n<tr>\n<td>sphere<\/td>\n<td>Austenitic stainless steel AISI 316<\/td>\n<\/tr>\n<tr>\n<td>tappet<\/td>\n<td>Stainless steel AISI 420 or 316<\/td>\n<\/tr>\n<tr>\n<td>interleave<\/td>\n<td>Austenitic stainless steel AISI 316L<\/td>\n<\/tr>\n<tr>\n<td>terminal (electrical engineering)<\/td>\n<td>Austenitic stainless steel AISI 316L<\/td>\n<\/tr>\n<tr>\n<td>*Standard handle<\/td>\n<td>Austenitic stainless steel AISI 316L<\/td>\n<\/tr>\n<tr>\n<td>*T-handle<\/td>\n<td>carbon steel<\/td>\n<\/tr>\n<tr>\n<td>Note: Standard and \"T\" bar handles are available separately.<\/td>\n<td><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h3>Weight (approximate)<\/h3>\n<table>\n<thead>\n<tr>\n<th>DN25<\/th>\n<th>6.0kg<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>DN32<\/td>\n<td>7.5kg<\/td>\n<\/tr>\n<tr>\n<td>DN40<\/td>\n<td>9.8kg<\/td>\n<\/tr>\n<tr>\n<td>DN50<\/td>\n<td>12.0kg<\/td>\n<\/tr>\n<tr>\n<td>DN65<\/td>\n<td>18.0kg<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h3>Product Description<\/h3>\n<p>Spirax Sarco KBV21 manual boiler drain valve with carbon steel body flange connection. Standard handle or T-handle available separately to meet boiler room codes. Operates drain valve with internal locking mechanism in austenitic stainless steel.<\/p>\n<h3>Ordering Instructions<\/h3>\n<p>Example: 2 - Spirax Sarco boiler drain valve KBV21, DN40, flange connection BS4504 PN40.<br \/>\n1 - KBV 20 standard handle<\/p>\n<h3>Spare parts available<\/h3>\n<p>Complete spare parts sets are available, including all seal and gasket assemblies, and ductile ribbed PTFE stem seals. Stems are also available. When ordering, please specify the valve type, application (e.g., boiler blowdown), and size (DIN).<\/p>\n<p><img fetchpriority=\"high\" decoding=\"async\" class=\"alignnone size-full wp-image-4991\" src=\"https:\/\/www.shopvalves.com\/wp-content\/uploads\/2025\/07\/img_1.png\" alt=\"Spirax Sarco Spirax Sarco KBV21 Manual Boiler Drain Valve Structural Drawing\" width=\"1090\" height=\"1482\" srcset=\"https:\/\/www.shopvalves.com\/wp-content\/uploads\/2025\/07\/img_1.png 1090w, https:\/\/www.shopvalves.com\/wp-content\/uploads\/2025\/07\/img_1-221x300.png 221w, https:\/\/www.shopvalves.com\/wp-content\/uploads\/2025\/07\/img_1-753x1024.png 753w, https:\/\/www.shopvalves.com\/wp-content\/uploads\/2025\/07\/img_1-768x1044.png 768w, https:\/\/www.shopvalves.com\/wp-content\/uploads\/2025\/07\/img_1-9x12.png 9w, https:\/\/www.shopvalves.com\/wp-content\/uploads\/2025\/07\/img_1-600x816.png 600w\" sizes=\"(max-width: 1090px) 100vw, 1090px\" \/><\/p>\n<p><!-- \u6280\u672f\u8d44\u6599\u4e0b\u8f7d\u533a\u5757 --><\/p>\n<div class=\"valve-documents\">\n<h3 class=\"doc-title\">Technical Data Download<\/h3>\n<div class=\"doc-links\"><a class=\"doc-link\" href=\"https:\/\/doc.shopvalves.com\/KBV21-IM-P405-CN-ZH.pdf\" target=\"_blank\" rel=\"noopener\">KBV21-IM-P405-CN-ZH.pdf<\/a><br \/>\n<a class=\"doc-link\" href=\"https:\/\/doc.shopvalves.com\/TI-P405-49-Chinese.pdf\" target=\"_blank\" rel=\"noopener\">TI-P405-49-Chinese.pdf<\/a><\/div>\n<\/div>","protected":false},"excerpt":{"rendered":"<p>Spirax Sarco Spirax Sarco KBV21 manual boiler drain valve consists of a carbon steel ball valve with a reinforced PTFE seat and a stainless steel manual hand...<\/p>","protected":false},"featured_media":4992,"template":"","meta":{"_kadence_starter_templates_imported_post":false,"_kad_post_transparent":"default","_kad_post_title":"","_kad_post_layout":"default","_kad_post_sidebar_id":"","_kad_post_content_style":"default","_kad_post_vertical_padding":"default","_kad_post_feature":"","_kad_post_feature_position":"","_kad_post_header":false,"_kad_post_footer":false},"product_brand":[24],"product_cat":[88,46],"product_tag":[],"class_list":{"0":"post-4990","1":"product","2":"type-product","3":"status-publish","4":"has-post-thumbnail","6":"product_brand-spirax-sarco","7":"product_cat-blowdown-vessels","8":"product_cat-boiler-controls-and-systems","10":"first","11":"instock","12":"sale","13":"shipping-taxable","14":"purchasable","15":"product-type-variable","16":"entry","17":"content-bg","18":"loop-entry"},"_links":{"self":[{"href":"https:\/\/www.shopvalves.com\/en\/wp-json\/wp\/v2\/product\/4990","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.shopvalves.com\/en\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/www.shopvalves.com\/en\/wp-json\/wp\/v2\/types\/product"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.shopvalves.com\/en\/wp-json\/wp\/v2\/media\/4992"}],"wp:attachment":[{"href":"https:\/\/www.shopvalves.com\/en\/wp-json\/wp\/v2\/media?parent=4990"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/www.shopvalves.com\/en\/wp-json\/wp\/v2\/product_brand?post=4990"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/www.shopvalves.com\/en\/wp-json\/wp\/v2\/product_cat?post=4990"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/www.shopvalves.com\/en\/wp-json\/wp\/v2\/product_tag?post=4990"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}